Were you at the game or following from elsewhere?
Have your say on Liverpool's performance
Come back to this page on Wednesday to find a selection of your replies
Four matches make up Tuesday's Champions League action, and we will bring you every moment.
All kick-off times 20:00 GMT unless stated:
Barcelona v Benfica (agg 1-0) - kick-off 17:45
Bayer Leverkusen v Bayern Munich (agg 0-3)
Inter Milan v Feyenoord (agg 2-0)
Liverpool v Paris St-Germain (agg 1-0) - BBC Radio 5 Live commentary
Pat Nevin
Former footballer and presenter
Image source, Getty ImagesSouthampton being 1-0 up against Liverpool at half-time was arguably the best thing that could have happened to Arne Slot's side, it certainly added to the entertainment. With all the other teams knocking each other out beneath the champions elect, and the Reds a goal up against PSG in the Champions League with the second leg at home, there was at least the theoretical danger of some complacency setting in.
Slot was all over the team after a less than energetic first 45 minutes, making three substitutions as early as half time and he clearly had a go at the group in the dressing room during the interval. He wouldn't let it lie post-match either. He underlined that the intensity, high energy and going "all in" for every game is non-negotiable for him.
These are the words of a winner but it is also very tough on players during such a heavy schedule. Their work rate in Paris during the week was exceptional and some players will have to manage their fitness levels for some huge fixtures to come, they are only human no matter how much you pay them. Mohamed Salah certainly knows how to rest in games and thank goodness he does.
Slot at one point said that he "didn't want his players to conserve energy", which is the first time I reckon I have not been fully onside with the Dutchman. Jurgen Klopp used to say just that in the early days at Anfield, but it soon leads to burnout.
You have to have some awareness, especially with players in their thirties, but then again maybe this is why certain stars haven't yet been given those new long-term contracts.
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Diogo Jota says he has endured "a difficult season" and doesn't think he's in his "best form" but says he feels he can turn things around at a key stage in the season as Liverpool prepare to face PSG on Tuesday in the Champions League.
The Portugal international hasn't scored since January and has been in and out of the team after struggling with injury issues.
Liverpool boss Arne Slot has been reacting to reported comments about his side.
Paris St-Germain, who visit Anfield trailing 1-0 on aggregate on Tuesday, are said to believe they have faced better English sides this season.
Slot told reporters he thinks there is a wider context to the reported comments.
Liverpool are contemplating whether to make a move for Brighton's Netherlands defender Jan Paul van Hecke, 24. (GiveMeSport), external
Want more transfer stories? Read Tuesday's full gossip column
Image source, Getty ImagesParis St-Germain boss Luis Enrique says whoever wins Tuesday's last-16 tie at Anfield will "go through to the final" in the Champions League.
Despite dominating the first leg, PSG travel to Liverpool seeking to overhaul a1-0 deficit from the first leg.
"Even though we're trailing, we will be playing our own game from the outset," Enrique said. "Regardless of the result (in Paris) we wouldn't do anything different.
"At the moment we are out so our only option is to go out and win and that is what is driving us.
"I'm not going to give away who we are going to play or how we are going to play. But over the course of two games, we will see two of the best teams in Europe, two contenders for the final and whoever goes through will go through to the final."
The PSG boss is also confident his team will be able to handle the pressure of playing at a "historic stadium".
"We know what Liverpool means with a historic stadium and a wonderful history," he said. "It's a huge source of motivation for the players and we want to show we are capable of putting in a performance.
"It is difficult to manage one's emotions and feelings. These are not easy games to prepare for and it is not easy to be at 100 per cent.
"But you don't want to be at 105 or 110 per cent because you could get carried away so you have to manage your emotions in the best possible way."
Nicola Pearson
BBC Sport journalist
Arne Slot has been speaking to the media before Tuesday's Champions League last-16 second leg against Paris St-Germain (kick-off 20:00 GMT).
Here are the key lines from his news conference:
Slot confirmed Cody Gakpo "will be fit to be in the squad" having trained for the first time on Monday.
On comments made by PSG boss Luis Enrique about his Ligue 1 side having nothing to lose: "They have a game of football to lose. We do as well. I do think they have been at this stage of tournament for many years. Last season they reached the semi-finals - we were not even in this competition last year! The season before, this was the round we were knocked out. These teams [like PSG] are normally going quite far into Europe."
On what Liverpool need to improve after their first-leg performance: "Some said we played poorly – I don't agree. I think they [PSG] played tremendously well. I don't think we have played a team this season that has combined that much quality with that much intensity, but I do think we can do better. I'm not saying we played poorly but we are a better team than we were last week. We need to prove that tomorrow with the help of our fans."
Slot does not believe that suggestions PSG were surprised by Liverpool's level last week will give his players extra motivation: "I don't think anyone needs more motivation. Not our players or theirs. If you play in knockout stages at Anfield with one of best teams in Europe - them and us - no-one needs any kind of motivation."
Asked if this kind of week with big games is what made him want to be Reds boss, he said: "There are many reasons why I wanted to be Liverpool manager. First of all, because of the history; second, because of the quality of players and third, because you expect us to be in these kind of moments. You want to compete for every trophy and at this club you expect to do so."
The head coach said "you don't dream at all" in a week like this and his only focus is to "prepare the team in the best way".
He added: "When you have games like last week you wonder: 'Do I even go to sleep or do I have to watch more?'"
On having a lead to defend: "Is it different? No. We play every game to try and win. We tried to do that last week. It wasn't our intention to be low all the time. We tried to play a different game to over there, but sometimes teams, with the help of fans, that [performance] happens. Our intention is always the same - we are not going to go for a draw. We want to win every single game."
Listen to live commentary of Liverpool v PSG from 20:00 GMT on Tuesday on BBC Sounds
Image source, Getty ImagesLiverpool forward Diogo Jota says he will always try to do his best "no matter what" after struggling for form and fitness this season.
The 28-year-old has missed a number of matches through injury and had to settle for coming off the bench as he has tried to regain a spot in the team.
In total, he has played 27 matches across all competitions this campaign, scoring eight goals and providing three assists.
"It has been a difficult season for me personally," Jota said before Tuesday's Champions League second leg against PSG.
"I have had a few complications, but this [coming] month or two are the ones that matter the most and decide things. I don't feel I am at my best performances yet at the moment but by playing, I feel I can get there.
"I always try to do my best no matter what. I don't play alone - it's not an individual sport. There are lots of things you can't control."
The Portugal international started in the Parc des Princes last week and will target making an impact in the return leg at Anfield, four years to the day since his last goal in the competition.
"Stats are also a part of today's game but they don't say everything," he said. "Obviously I want to score but that is not a factor that will impact my game tomorrow.
"If I don't score and we go through, then I don't mind adding some more days onto [the statistic]."
Jordan Chamberlain
Fan writer
Image source, Getty ImagesAlexis Mac Allister has been the most unheralded of Liverpool's three starting midfielders this season, but he is perhaps the most important.
Arne Slot rested him against Southampton, and the Reds put in a pitiful first-half performance that saw them 1-0 down against the worst side in the Premier League.
But everything changed when Mac Allister came on at half-time and within 10 minutes Liverpool had scored twice and the match was effectively won.
He passes the ball through the lines at will, enabling Liverpool to transition more quickly and get his attackers on the half-turn. Before his entrance, all the passes into the forwards went to their feet when they were static, so it was too easy for Southampton to defend.
Mac Allister gets stuck in, too. He tackles, presses and his positioning is exceptional. He really is the all-round package in terms of a progressive central midfielder.
Ryan Gravenberch and Dominik Szoboszlai looked tired against Southampton, but it is no surprise - they have barely had a rest all season. Slot will use those two and Mac Allister against PSG in the Champions League and Newcastle United in the League Cup final.
Let's hope they can get through it before the international break. By then, Liverpool may have two trophies wrapped up and be in the quarters of the Champions League - in hope of a potential treble.
Find more from Jordan Chamberlain at Empire of the Kop, external
Image source, Getty ImagesFormer West Ham midfielder Nigel Reo-Coker says Liverpool will want to get the Premier League title wrapped up "as quickly as possible" and that Arsenal have given them an "open door to get it done".
On BBC Radio 5 Live's Football Daily podcast he said: "I think if you are a Liverpool player right now, as much as they have surprised everyone this season, nobody expected them to be in this position and this good under new manager Arne Slot.
"They have been sensational, only losing one game this season to Nottingham Forest and they are going to want to get this done as quickly as possible because they are still competing in the Champions League until at least next week, so wrapping up the Premier League title is the priority and Arsenal have given them an open door to get it done."
Image source, Getty ImagesLiverpool defender Andy Robertson is expecting "a tough game" against Paris St-Germain in the second leg of their Champions League last 16 tie and says the Reds will need to play "a lot better" than they did in the first leg against their Ligue 1 opponents.
Arne Slot's side go into the second leg with a 1-0 advantage, thanks to Harvey Elliott's 87th-minute winner at Parc des Princes last week, and will be hoping for a similar result to see them progress to the quarter-finals of the competition.
Speaking to BBC Radio Merseyside ahead of the second leg at Anfield on Tuesday night, Robertson said: "I think they have shown how good they can be. They are probably the best team we have played this season.
"We have got the lead, which is important, but we can obviously play better than what we did in the first leg and that is clear. We will have to play better because we can't rely on Alisson playing the game of his life every game.
"Hopefully the crowd can get behind us, like they usually do on Champions League nights, and hopefully we can get through.
"That's the aim but we have to play a lot better than we did against Southampton in the league and probably the whole 90 minutes against PSG [in the first leg]. We need to play better, there is no denying that.
"We have to be a little bit more front-footed and things like that, but the game plan will be clear.
"Hopefully we will be sat here talking on Tuesday night about being through to the quarter-finals.
"It's not going to be easy but, if we play at our best and believe we can beat any team, we will be the ones in the last eight."
Image source, Getty ImagesWe asked for your views on Liverpool's Premier League match against Southampton.
Here are some of your comments:
Liverpool fans
Jason: First half we seemed flat and unimaginative. Arne Slot again being ruthless and those substitutions breathed in some flair and energy to break down Southampton. Diaz had a complete turnaround performance in the second half with his direct dribbling which I would love to see this more from him.
Thilani: At this point Liverpool are doing what champions do; grinding results and getting the points!
Karen: Thank you Southampton for the kick up the backside the reds needed. They thought the goals would just mount up very easily. If you hadn't scored first this match could well have finished a goalless draw. Second half, Liverpool were more Champions elect.
Southampton:
Shearsy: Decent performance. Harsh penalties, but the players gave everything today. We march on.
Matthew: Crumbled under pressure again at the start of the second half, but we had more dodgy VAR decisions. It's looking OK to get at least one more win to get that record gone.
Shawn: Battling but you can't beat the referee as well. Equaliser scored by player who should have been sent off if the ref had guts. Oh well, it was never going to go our way.
Image source, PA MediaLiverpool have agreed a "multi-year" deal that will see Adidas become the Reds' kit partner from 1 August.
The Premier League club previously partnered with Adidas between 1985-1996 and 2006-2012.
Nike have supplied Liverpool's kits since the start of the 2020-21 season.
Liverpool chief executive Billy Hogan said: "Everyone at the club is incredibly excited to welcome Adidas back into the LFC family.
"We have enjoyed fantastic success together in the past and created some of the most iconic Liverpool kits of all time.
"Adidas and Liverpool share an ambition of success and we couldn't be more excited to partner together again as we look forward to creating more incredible kits to help drive on pitch performance.
"We'd like to thank Nike for their support over the past five years and wish them well for the future."
Liverpool, Arsenal and Chelsea have been keeping tabs on 27-year-old Inter Milan forward Marcus Thuram. (TBR Football), external
Highlights and analysis from Saturday's six Premier League fixtures.
If you missed Match of the Day, you can catch up now on BBC iPlayer.
Listen back to full match commentaries on BBC Sounds:
Image source, Getty ImagesArne Slot spoke to BBC Match of the Day after Liverpool's victory against Southampton: "It's a sign of a good team that you can win in different ways. It was a poor performance first half - not only because of the way we played but also because of the energy we brought.
"The only good thing in the first 45 minutes was that they saved their energy [for Paris St-Germain on Tuesday] and didn't run at all!
"I know these players are capable of doing much, much better. That is what I expect this week. They were not the energy levels I am used to with these players."
On his side's 16 point lead at the top: "It's 16 for now but that can be down to seven by the time we play Everton in a few weeks [Arsenal have three Premier League games before Liverpool next play in the top-flight].
