Things haven't gone Barcelona's way so far this evening, with La Liga leaders Atletico Madrid beating Athletic Bilbao 2-1 to move six points clear of Ronald Koeman's side at the top in Spain.

They won't care much about that tonight if they make it through to the quarter-final draw.

Barca have settled on the ball in the early stages at the Parc des Princes.

Trent Alexander-Arnold pings a long ball down the pitch looking for Sadio Mane as the Reds attack early but the RB Leipzig defence is well placed to clear.

We're up and running in both of tonight's Champions League games.

BBC Radio 5 Live

Almost time for kick off.

Don't forget you can listen to live commentary on BBC Radio 5 live and online via this page.

A 6-5 aggregate win versus PSG in 2016-17, after a 4-0 away defeat.

An away goals loss against Roma in 2017-18, after a 4-1 home win.

A 4-3 aggregate defeat versus Liverpool in 2018-19, after a 3-0 home victory.

Barcelona have been involved in their fair share of dramatic Champions League comebacks in recent years.

Can they add another to the record books? It's almost time to find out.

Liverpool

Liverpool boss Jurgen Klopp, speaking to BT Sport: "The good thing about this is that it is Champions League and as strange as it is it is our home game. We have to be solid defensively, but we have to do good things offensively too. It is no good us sitting back and trying to defend the lead. Tonight you will see two teams trying to go through. It will be exciting.

"We always want to have Fabinho in midfield but it was not always possible. You need to defend in spaces, including midfield. We have an experienced midfield and team, maybe apart from the last line. The opponent will ask us everything."

Stephen Warnock
Ex-Aston Villa and Liverpool defender on BBC Radio 5 Live

It is a very difficult one for Liverpool tonight because you look at their defensive record at the moment and their confidence, how do they approach the game? Do you try and put it to bed and score the next goal? Do you sit on it and play on the counter-attack, but defensively are they good enough to do that and trust themselves enough?

How are the players feeling at the moment? Confidence wise do they think they can win this? They won the first leg from two mistakes and Leipzig are a dangerous team going forward. They are a free-scoring team and possess huge danger to Liverpool.

Image source, Gracenote

Simon Gleave, head of sports analysis, Gracenote:"Liverpool's first leg victory against Leipzig has increased their chance of winning the Champions League because the Reds are now favourites to reach the quarter-finals. This has raised the club's chance of winning the competition to around 7%.

"This is still lower than earlier in the competition because of Liverpool's spectacular fall in the Euro Club Index, external. They have dropped from second place in Europe at the turn of the year to seventh place now.

"Liverpool's chance of a place in the last eight at the expense of Leipzig is now around 88% according to the Euro Club Index."

Both PSG and Barcelona recorded comfortable victories at the weekend, as the French champions beat Brest 3-0 to progress in the Coupe de France and Barca won 2-0 against Osasuna in La Liga.

Mauricio Pochettino's PSG have won their past three games without conceding, while Ronald Koeman's side have won four-in-a-row in all competitions by an aggregate score of 10-0.

Barca also overturned a 2-0 first leg deficit against Sevilla in the Copa del Rey last week, winning the return game 3-0...

Sander Westerveld
Former Liverpool goalkeeper on Radio 5 Live

Liverpool have been really unlucky with the amount of injuries that they've had. The summer break was really short, and they've had to play a lot of games in a short period.

Mentally seems to be the biggest issue in the moment. If you're not scoring those goals, and you're making one error and losing games, the mental strength that Liverpool did have has changed.

Image source, Getty Images

Kylian Mbappe scored a stunning hat-trick against Barcelona in the first leg to leave PSG in command of this tie.

The 22-year-old, who scored his 25th goal of the season at the weekend, has been directly involved in 39 goals in his 41 Champions League appearances. Simply crazy numbers.

If he scores tonight, he will become the youngest player to reach 25 goals in the Champions League, aged 22 years and 80 days.

Who is the current youngest player to reach 25 goals in the competition?

Lionel Messi, of course, who reached the milestone against Arsenal in 2010, aged 22 years and 286 days.

So, can Barcelona do it?

No team has ever progressed from a European Cup/Champions League knockout tie over two legs after losing the first at home by three goals.

"It is always different to have a result like this," manager Ronald Koeman said. "Losing 4-1 at home means we have to score goals away from home and it's more complicated but nothing is impossible.

"We believe in ourselves - we know we are Barca and have to win and will demonstrate this mentality."

Image source, Getty Images

Image source, .

RB Leipzig could be forgiven for being scarred by their last "away" trip against English opposition.

The German side suffered the heaviest defeat in their short European history when they were stunned 5-0 by Manchester United in the Champions League at Old Trafford last October.

But the Bundesliga side beat United 3-2 in the reverse fixture and progressed from the group alongside Paris St-Germain, and they will be just as confident of overturning a 2-0 deficit tonight.

"We have our chance in the Champions League," Leipzig midfielder Tyler Adams told BBC Sport. "We are still alive and the vibes are good in the team, we are all positive. The pressure is more on them, not on us. We are the underdog."

Read more from Alex Bysouth's interview with Adams here.

Stephen Warnock
Ex-Aston Villa and Liverpool defender on BBC Radio 5 Live

Fabinho gives protection to the backline and that has been key for a long time now. It allows Trent Alexander-Arnold and Andy Robertson to go forward. He is a player that senses danger and it allows the front three to press because they know there will be an organised midfield behind them.

Fabinho knows when to give away a foul too. He does that job extremely well.

Liverpool make five changes from the side tat lost to Fulham at Anfield. Trent Alexander-Arnold is back at right-back, replacing Neco Williams, while Ozan Kabak partners Nat Phillips at centre-back, with Rhys Williams dropping out.

In midfield, Fabinho and Thiago replace James Milner and Nabi Keita, while up front Sadio Mane takes the place of Xherdan Shaqiri.

Roberto Firmino remains absent through injury.

Liverpool: Alisson, Alexander-Arnold, Phillips, Kabak, Robertson, Thiago, Fabinho, Wijnaldum, Mane, Salah, Jota.

Subs: Milner, Keita, Adrian, Oxlade-Chamberlain, Jones, Tsimikas, Shaqiri, Origi, Ben Davies, Rhys Williams, Neco Williams, Harvey Davies.

Image source, .

Two changes for RB Leipzig from the side that won 3-0 against Freiburg.

Emil Forsberg comes in for ex-Crystal Palace forward Alexander Sorloth, while Marcel Sabitzer replaces Amadou Haidara in midfield.

RB Leipzig: Gulacsi, Mukiele, Upamecano, Klostermann, Kampl, Adams, Olmo, Sabitzer, Nkunku, Poulsen, Forsberg.

Subs: Orban, Konate, Haidara, Hwang, Sorloth, Samardzic, Kluivert, Halstenberg, Martinez, Henrichs.

Image source, .

Image source, BBC Sport

PSG boss Mauricio Pochettino makes eight changes from the side that defeated Stade Brest in the French Cup last Saturday.

Only Marco Verratti, Kylian Mbappe and Julian Draxler retain their places as the likes of Keylor Navas, Presnel Kimpembe, Marquinhos and Idrissa Gueye all come into a much more familiar line up.

PSG XI: Navas, Florenzi, Marquinhos, Kimpembe, Kurzawa, Gueye, Paredes, Verratti, Draxler, Icardi, Mbappe-Lottin.

Subs: Kehrer, Di Maria, Rafinha, Pereira, Rico, Sarabia, Herrera, Diallo, Bakker, Dagba, Pembele, Michut.

Image source, BBC Sport

Barcelona manager Ronald Koeman makes one change to the side that started their 2-0 La Liga win against Osasuna at the weekend.

Forward Ousmane Dembele replaces defender Samuel Umtiti.

Barcelona XI: Ter Stegen, Dest, Mingueza, Lenglet, Jordi Alba, de Jong, Sergio Busquets, Gonzalez, Griezmann, Messi, Dembele.

Subs: Pjanic, Braithwaite, Puig, Neto, Trincao, Fernandes, Umtiti, Firpo, Pena, Moriba, De la Fuente.

What do you think, Liverpool fans? Agree with Sander that tonight could change Liverpool's fortunes? Why do you feel things haven't clicked this season?

Have your say on that or tonight's games in general via #bbcfootball or text in on 81111 (UK only)