Liverpool are all in red, attacking the goal to the left as we look on. Napoli are in their familiar sky blue. The officials have gone retro - all in black. Rare.

Also under way on an awful looking Wembley pitch.

Under way in Italy...

Spurs boss Mauricio Pochettino insists there are no hard feelings as he goes up against the man who effectively ended his playing career.

Current Barcelona manager Ernesto Valverde dropped Pochettino, then 34, when he took over at Espanyol in 2006 - and the Argentine ended up retiring.

"That day it was difficult to understand his position, but I talked to him in pre-season, when we played Barcelona in Los Angeles, and I completely understand," said Pochettino.

"He arrived at Espanyol at not a good time for me. I could not see it at the time - but I can now. In football you are protected by this bubble."

Valverde said this week: "When you're a coach, you have to make decisions, always trying to choose the best players for your team," he told a news conference. "I've had to do it over a long time. Mauricio has also had to make his own.

"I made the decision to do without Pochettino. He has also had to make some [decisions] that someone wouldn't like. We have a good relationship and we respect each other."

Image source, Getty Images

Napoli boss Carlo Ancelotti said he was surprised by the choice of Viktor Kassai to referee the match.

The Hungarian was in charge when Ancelotti's Bayern Munich side lost 4-2 after extra-time to Real Madrid in a 2017 Champions League quarter-final second leg.

The official sent off Bayern midfielder Arturo Vidal for two bookable offences in the match, while Cristiano Ronaldo scored in extra time from an offside position as Real Madrid won 6-3 on aggregate.

"The referee brings back bad memories for me relating to my last team," said Ancelotti.

"I'm surprised by the referee designation. A long time has passed and time usually heals certain things, but does not banish them."

Guillem Balague
Spanish football journalist on BBC Radio 5 live

Barcelona have struggled to replace players, they haven't bought anyone in for Neymar, for Iniesta and eventually for Sergio Busquets.

There are new players in the likes of Arthur and Ousmane Dembele but they're still adapting.

Don: This shouldn't be a debate. Being at the PSG game, even though Sturridge played well enough, scoring a goal, he just physically could not press with the same intensity and intelligence that Firmino can, which disrupts our entire system. Love him though.

Image source, .

Jurgen Klopp was sent off on his last visit to Napoli in 2013, as Borussia Dortmund manager.

He berated the fourth official for taking too long to allow defender Neven Subotic to return to the pitch in his side's 2-1 defeat.

"It was not my best behaviour," he said this week. "Since then nothing happened any more, so it was my last time when I was a bit too excited.

"It was not nice sitting in the stand, getting all the comments, so I decided to watch the second half of the match from the groundsman's room - with a big picture of Diego Maradona on the wall."

Andy Townsend
Ex-Chelsea midfielder on BBC Radio 5 live

Harry Kane is the best goal-scorer in our league and I don't think anyone will doubt that.

But to get on that level of Messi and Ronaldo and hitting 40 goals a season, it's incredibly tough especially in the Premier League.

If anyone can do it though, it's Harry Kane, he's got age on his side but he needs to have more consistent form to get in that bracket.

Image source, EPA

Tottenham striker Harry Kane hopes he can one day emulate, and perhaps break, the goalscoring records of Barcelona forward Lionel Messi.

The 25-year-old's two goals against Huddersfield last weekend put him on 145 for Tottenham, taking him past Jermain Defoe and into fifth place on the club's top scorers list.

However, he is a long way behind Argentine Messi, who has scored 560 goals in 646 games for Barcelona, with 103 of those coming in the Champions League.

"He's definitely set the standard for the rest of us and it motivates me to get even better," Kane said.

"Hopefully one day I can score as many, if not more, than he has."

BBC Radio 5 live

Andy Townsend and John Murray are in position at Wembley for today's game. Live commentary available on 5 live - and on this page.

Image source, BBC 5 live

Phil McNulty
BBC Sport chief football writer at Wembley

Spurs and Barcelona's players are out warming up and plenty of attention being paid to that very odd-looking area of the playing surface 15 yards either side of the halfway line, a leftover from Anthony Joshua's boxing feats.

It does not look clever at all, but I'm pretty sure the likes of Lionel Messi will be able to handle it. It is not Stoke on a cold Tuesday night after all.

Spurs produced a memorable night here last November to outclass the eventual Champions League winners Real Madrid. They might need something similar tonight.

Liverpool

Liverpool boss Jurgen Klopp speaking to BT Sport: "Hendo [Jordan Henderson] has played a lot of games and still hasn't had the perfect pre-season. Naby Keita's specific skills will help in between the lines.

"We want a good result. We are not 100% sure about the line-up from Napoli but it looks like a 4-3-3 and it may change a little bit. They have put one more midfielder in and it looks a little more defensive. They have respected us and we will do that with them.

"This is a test. It is a football game in the group stage so we should not waste minutes and we will try to win the game. If we get a point then we will respect that but we should try to win."

Image source, Getty Images

It's all over, Schalke grab the win late on.

It's all over. The win was as dominant as the scoreline suggests. If anything it should have been more.

Guillem Balague
Spanish football journalist

Image source, .

Two points out of a possible nine in the league and eight goals conceded in their past seven games suggests a vulnerable team way short of their best form.

Much has been made of uncharacteristic mistakes by centre-back Gerard Pique, with three errors in recent games leading directly to opposition goals. But while he certainly needs to improve his intensity and concentration, Barca's problems go a lot deeper than that.

They are struggling to maintain pressure high up the pitch, and with Ivan Rakitic playing in a more advanced role, the pivotal Sergio Busquets is cutting an isolated figure further back in midfield.

And there is a deeper problem. Too often this season their attacks have been more individual than collective and sometimes too direct. When Barcelona attack as a unit they defend as one as well - but right now, when they lose the ball, there are often big gaps between defence and midfield. Opponents have been exploiting this space.

Read Guillem's preview of the game here.

Neymar is the first player to score two free-kicks in a Champions League game since Cristiano Ronaldo in Real Madrid's 5-2 win at FC Zurich on 15 September 2009.

Image source, Getty Images

Image source, EPA

Eric Maxim Choupo-Moting shoots wide and now Adrian Rabiot goes close with a header.

Liverpool manager Jurgen Klopp has dismissed praise from Napoli boss Carlo Ancelotti as "tactics".

Ancelotti called the Reds "one of the strongest teams in Europe", before the match in Naples on Wednesday.

"I like Carlo Ancelotti. In Germany, we say he's a smart fox," said Klopp.

"He's said very positive things about us and nice things about me before a game. It's nice, but it's tactics. Carlo is so long in the business."

Image source, Reuters