Pep Guardiola and Lionel Messi will be reunited this evening as Manchester City look to avenge their 2-0 defeat to Paris Saint-Germain in September's reverse fixture.
PSG new-boy Messi scored his first goal for Les Parisiens with a trademark curling finish that night as Mauricio Pochettino’s men triumphed at the Parc des Princes.
But the Premier League side lead group A by a point and victory would confirm top spot for Guardiola and his team.
So, ahead of tonight’s mouthwatering tussle, how can the Citizens gain revenge over PSG?
Minimising Messi's magic
Guardiola knows more than most about the difficulties of stopping Messi.
Speaking ahead of the game, he said: "It’s so difficult. Sometimes when he [Messi] has the ball he doesn’t know what he’s going to do — so imagine you have to know what he is going to do.
"There are players who you can say if they will go right or left. When he has the ball, not even he knows.
"But I am still glad and happy that he is still playing, at the level he plays and with the quality, so it will be nice to face him."
The Argentine dominated the headlines after the first meeting between these sides but City have plenty of weapons of their own.
Key man Cancelo
Full-backs have become an increasingly important part of a manager’s tactical armoury in recent years.
Guardiola has influenced the likes of Dani Alves, Philipp Lahm and Joshua Kimmich. His latest project is Joao Cancelo.
The defender's stunning outside-of-the-boot assist for Raheem Sterling’s goal against Everton on Sunday was one which any of the world’s top playmakers would be proud of.
And City midfielder Ilkay Gundogan has been impressed by the Portuguese’s displays.
He said: "I think with Joao in the last few months he has been able to minimise mistakes and maximise the outcome of his individual situations.
"He rarely loses a ball and with the ball it feels like he always finds solutions, with a dribble, a pass, a decisive moment."
Cancelo has already scored twice in this season's Champions League as well as supplying three assists and creating 10 chances.
No full-back in the competition has attempted more take-ons (15), had more shots on target (three) or completed more final-third passes (103).
Tactically, the Portuguese is City’s most important player and the role he plays under Guardiola will be key to breaking down PSG.
The false nine
The English champions have regularly played without a striker for large parts of games.
This was perhaps most evident in their dismantling of Manchester United when a front three of Phil Foden, Bernardo Silva and Gabriel Jesus interchanged effectively, supported by a deep-lying Kevin De Bruyne.
The wide players cut in from the flanks, leaving United’s centre-backs confused as they had no obvious assignment or man to mark.
The false nine role is one Ferran Torres and Gundogan have also performed in the past.
City could do the same against PSG in an attempt to unsettle the French side’s defence. Whoever gets the nod up front could end up playing most of their football in midfield.
The importance of wingers
The wide areas will be very important to City’s attacking play with Guardiola’s teams instructed to maintain width and high starting positions at all times.
With full-backs cutting inside and centre-forwards dropping into midfield, there are large areas for the likes of Sterling, Foden, Jack Grealish and Riyad Mahrez to operate in.
Sterling played well on the right against Everton — grabbing a goal in the process — and Guardiola is not averse to using orthodox wingers to provide the width in his side.
This stretches the opposition and, coupled with the false nine, can create space between opposition defenders for both passes and runs into the box.
Guardiola has often been accused of overthinking his tactical setup for one-off big games. Champions League exits against Liverpool, Tottenham, Monaco and Lyon during his time in England have all been criticised.
Although tonight’s meeting at the Etihad is unlikely to make or break City’s Champions League campaign, it will provide a stern test of their mettle and give an indicator as to whether the Citizens can go one better than last season and win their first European title.
Stopping Messi — along with Kylian Mbappe and Neymar — will be at the forefront of Guardiola’s thinking. But the former Barcelona coach is a front-foot tactician and will go out to attack PSG.
Both teams are likely to advance with minimal fuss but this tie has all the makings of a Champions League classic.