There is no Lionel Messi in the Barcelona starting XI.

For Tottenham, Harry Kane and Christian Eriksen return.

Full team news to follow.

Liverpool

Sadio Mane is in the Liverpool starting XI tonight as Jordan Henderson also returns in three changes from the weekend.

Liverpool: Alisson, Alexander-Arnold, Matip, van Dijk, Robertson, Wijnaldum, Henderson, Milner, Salah, Firmino, Mane.

Subs: Mignolet, Fabinho, Lovren, Keita, Sturridge, Shaqiri, Origi.

Napoli: Ospina, Maksimovic, Albiol, Koulibaly, Rui, Allan, Hamsik, Fabian, Callejon, Mertens, Insigne.

Subs: Karnezis, Ounas, Zielinski, Hysaj, Ghoulam, Diawara, Milik.

Full team news to come.

If PSG draw at Red Star and Liverpool win, the Reds, PSG and Napoli will be level on nine points.

They would be separated by their record in matches against each other - essentially a mini three-team group, discounting results against Red Star.

A Liverpool victory tonight would see them top that on six points, with PSG and Napoli level on five points.

Who progresses out of those two would depend on Napoli's result at Anfield.

Image source, BBC Sport

Liverpool have to win.

If they do, and PSG are beaten at Red Star Belgrade, then it's a simple picture: both Liverpool and Napoli will go through. Who finishes top will depend on the result at Anfield.

There are two ways Liverpool can finish above Napoli - with a 1-0 win or with a victory by two goals or more.

Remember: it's not goal difference that separates teams level on points but the head-to-head record between sides. Exactly.

A 1-0 win would edge them through on goals scored, likewise a win by two goals or more. But if Napoli lose by one goal and score themselves, they would have the upper hand on away goals over their two games.

But wait, there is more...

Image source, BBC Sport

Spurs are second, ahead of Inter because they have a better head-to-head record in their two matches - they lead the Italians on away goals.

They lost 2-1 to Inter in the San Siro in their first meeting in September. So that's 2-2 on aggregate, as it were, after their 1-0 home win.

This all means that if Spurs finish level on points with Inter they will be the ones who go through.

So, Spurs will qualify if their result at Barcelona matches or betters Inter's result at home to PSV.

Which team has the harder task?

Tottenham are in Barcelona. A win guarantees them a spot in the last 16. Anything else and they're relying on Inter Milan failing to beat PSV at home.

Liverpool welcome Napoli to Anfield. They really do have to win, although confusingly, even that may not be enough.

I can feel some permutations coming on.

Image source, Reuters

Crunch o'clock.

There is a crucial evening ahead for Liverpool and Tottenham.

The Champions League knockout stage awaits - can they get there?

Both teams have their fate in their own hands: victory will mean progress.

There's only one slight issue...

Image source, Reuters