Key storylines from Matchday 2 of the Champions League, Europa League and Europa Conference League

European football is back - and boy how we missed it!

As ever, BT Sport will bring you exclusive live coverage of the Champions League, Europa League and the newly-formed Europa Conference League as the action continues this week.

Matchday 2 has a lot to live up to after Cristiano Ronaldo’s first Champions League appearance for Manchester United since the 2009 final and to Lionel Messi’s tournament debut in the royal blue of Paris Saint-Germain.

Matchday 1 was packed with captivating storylines and the drama is set to continue this week so to whet your appetite ahead of a thrilling week of games on BT Sport, here are the games to look out for.

Tuesday 28 September

You’d be hard-pressed to pick a better reason to tune in to the Champions League on Tuesday night than to catch Lionel Messi and Pep Guardiola's reunion as PSG welcome Man City.

Messi was a mainstay of Guardiola's Barcelona side that won 14 major titles between 2008 and 2012 - including two Champions League trophies - and had been linked with a switch to City before opting to join the French giants.

Like City, PSG are yet to win European football's top prize and Messi is hungry to help break the club's hoodoo and add a fifth Champions League medal to his own collection. 

"My dream is to win another Champions League, and I think this is the ideal place to be to do that," said Messi, but the Argentinian has made a slow start to life in Paris.

The 34-year-old has so far failed to score for his new club and looked puzzled when he was replaced by full-back Achraf Hakimi in a victory over Lyon 10 days ago.

The ex-Barca man exchanged words with manager Mauricio Pochettino as he walked off the pitch and the pair didn't shake hands.

The former Tottenham boss has since defended his decision to replace the six-time Ballon d'Or winner, saying: "I think we all know we have great players in this 35-man squad.

"Only 11 can play, we can't play more. The decisions in the game are made for the good of the team and each player," Pochettino told reporters.

"These are decisions that have to be made by the coach. As for his reaction, I asked him how he was, he said he was okay. That was it. That was our exchange."

The Argentinian missed PSG's midweek Ligue 1 clash with Metz through injury but the playmaker is expected to return to action for the visit of City on Tuesday night.

It will be a case of 'what might've been' for Messi night as he lines up against his former mentor, Guardiola - live on BT Sport 2HD and Ultimate from 7pm.

City began their campaign with a thrilling 6-3 victory over RB Leipzig at the Etihad a fortnight ago but Guardiola will be preparing his side for a far sterner test with Messi, Neymar and Kylian Mbappe lying in wait - the Champions League at its best!

Wednesday 29 September

It’s a tough act to follow Tuesday’s quality slate of matches, but Wednesday night should provide more than enough intrigue to keep you glued to your TV screens once again.

With the best of the games all kicking off at 8pm, you’ll need to fire up your BT Sport app for some second screen viewing to stay across all games as Manchester United vs Villarreal and Juventus vs Chelsea get underway at the same time.

Wednesday's main event sees United face-off against Villarreal in a repeat of last year’s Europa League final when Red Devils came agonisingly close to securing their first piece of silverware under Ole Gunnar Solskjaer, with David de Gea missing the crucial kick in a dramatic penalty shootout.

Now United and the Yellow Submarine renew hostilities with Solskjaer facing a must-win game following their shock 2-1 defeat to Swiss minnows Young Boys on opening night.

The Norwegian will be hoping for a more clinical performance at Old Trafford after a red card for Aaron Wan-Bissaka and Jesse Lingard's errant back-pass cost United in Matchday 1.

"In football in general, not just the Champions League, discipline is a huge part of the game," Solskjaer said in his post-match news conference. "A lack of concentration, make a mistake and you get punished, you get done.

"We've lost the opportunity to get three points, but we've got two home games next and we've got to focus on those two."

Avenging last summer's Europa League heartbreak is a must if United are to have any hope of progressing into the knockout stages and you can watch it all on BT Sport 3HD and Ultimate from 7.15pm.

High-flying Chelsea continue the defence of their Champions League crown at the same time on Wednesday evening, as they visit Serie A giants Juventus in a meeting between two European heavyweights. 

The Blues have been in imperious form since Thomas Tuchel replaced Frank Lampard as head coach and are many people's tip to go back-to-back in Europe.

Club record signing Romelu Lukaku has fitted seamlessly into Tuchel's blue machine and will be relishing a return to Italy having helped Inter wrestle the Scudetto from Juventus' grip last season.

For Juventus, a midweek meeting with the most in-form team in Europe could not be coming at a worse time, with the Old Lady struggling after an uncharacteristic slow start in Serie A.

With Cristiano Ronaldo gone, Juve boss Max Allegri will be hoping to turn his side's season around with a morale-boosting display against the European champions.

Our coverage of the Turin clash gets underway at 7pm on BT Sport 2HD and it's one you're not going to want to miss!

Thursday 30 September

Bringing the midweek football fiesta to a buzzing conclusion on Thursday, we’ve got Leicester, West Ham, Rangers and Celtic in Europa League – plus Tottenham in the Europa Conference League.

The early kick offs bring you two belters to look forward to, beginning with Leicester City's trip to Poland to face Legia Warsaw - live on BT Sport 2HD from 5.15pm.

Brendan Rodgers' side were denied the dream start to the group stages as they surrendered a two-goal lead to draw with Serie A giants Napoli at the King Power Stadium.

Now the Foxes head out on the road and will be determined to pick up a win to kick-start their campaign. 

Football fans north of the border will be focussed on the Czech capital where Rangers take on Sparta Prague from 5.15pm on BT Sport 3HD.

Steven Gerrard's side slipped to a disappointing 2-0 defeat to Lyon at Ibrox on Matchday 1, while arch rivals Celtic welcome Bayer Leverkusen to Glasgow from 7.45pm on the same channel.

Two weeks on from their heartbreaking 4-3 defeat to Real Betis, the Bhoys will also be looking to bounce back with the Old Firm sides in need of points.

David Moyes’ Hammers made a flying start in their Europa League bow, scoring two unanswered goals in an impressive away victory over Dinamo Zagreb.

The former Everton boss says he is "really excited" to not know the true potential of his West Ham team as they resume their European adventure.

Michail Antonio and Declan Rice both scored as the Hammers announced themselves in the competition with a dominant performance against the Croatian champions.

Moyes will be hoping for another talismanic performance from England international Rice, after the midfielder marked his 150th appearance for the club with a goal. 

"I think what he's [Rice] tried to do is take himself to the next level," said Moyes. "He's a terrific player and he's getting better.

"He's still only 22, he's a young boy with a big future. It's one step at a time, but he's doing really well for us. The ability to surge away from people, his power and speed, is a great trait."

The former Chelsea youth player has kicked on from his Euro 2020 exploits and, alongside Antonio, is helping Hammers fans to dare to dream of European glory.

Over in north London, the Tottenham Hotspur Stadium will host its first Europa Conference League game with Slovenia's NS Mura in town. 

Spurs' European campaign got off to an inauspicious start as substitute Pierre-Emile Hojbjerg's 76th-minute effort salvaged a 2-2 draw away at Rennes. 

New boss Nuno Espirito Santo has seen his attacking options decimated in recent weeks after wingers Lucas Moura and Steven Bergwijn limped off in Brittany, but more concerning is the form of the club's star striker Harry Kane.

The 29-year-old failed to register a single touch in Tottenham's chastening defeat at Selhurst Park and cut a despondent figure on the left-wing against Chelsea with the striker looking out of sorts since a summer move to Man City failed to materialise. 

With the England captain severly lacking in form, Nuno may opt to field his wantaway striker against Mura in a bid to build some much-needed confidence, with our coverage getting underway on BT Sport 2HD from 7.45pm.