Jack Grealish scored a goal and grabbed an assist on his Champions League debut as Manchester City thumped RB Leipzig in Pep Guardiola's 300th game in charge of the club.
Almost four months since tasting defeat in the final, City were back in action in Europe's elite competition, and they wasted little time in breaking the deadlock.
With 16 minutes on the clock, a devilish corner delivery from Grealish found Nathan Ake unmarked and he made no mistake with a powerful header.
Opinion: Grealish proves he belongs in the Champions League with dazzling debut
On his first start of the season, Kevin De Bruyne was at the heart of City's second when on 28 minutes he teased a beautiful cross to the back post and Nordi Mukiele could only head into the back of his own net.
Christopher Nkunku halved their advantage three minutes before half-time following a decent spell from the visitors, but Riyad Mahrez eased City's nerves from the penalty spot in added-time after Lukas Klostermann used his arm to block Ferran Torres' header.
Leipzig kept coming and six minutes after the restart the Germans found themselves back in the game when Nkunku scored his second of a memorable evening.
'The first of many' - Guardiola lauds Grealish after goal against Leipzig
Determined to dominate the headlines, however, was Grealish and he duly delivered on his big night. Collecting the ball on the right, he carved inside and curled a delicious shot into the top corner.
The visitors refused to give in as Nkunku netted his hat-trick with a fine solo effort, but just minutes later Joao Cancelo scored City's fifth with a sublime strike from 20 yards.
And just to complete a drama-filled night, Angelino was sent off for a second bookable offence against his former club, before substitute Gabriel Jesus grabbed a goal on his 200th appearance for the club.
Manchester City are back in action in the Champions League on September 28 when they travel to Paris Saint-Germain to face Lionel Messi and co.
TALKING POINT - Goals, goals, goals at the Etihad
And breathe. The Champions League is back at the Etihad with a bang.
What looked a tricky match for Manchester City on paper against last season's Bundesliga runners-up proved to be relatively simple on grass, even if there were a few questionable moments in defence.
Guardiola made four changes to the side that defeated Leicester on Saturday, with Oleksandr Zinchenko, De Bruyne, Ake and Mahrez coming in. The latter three were all involved in goals, but it was De Bruyne who stole the show. Despite playing just 11 minutes before tonight due to an ankle injury, the Belgian was back to his brilliant best, particularly in the first half. However, the moment of the game was saved for Grealish, who scored a great goal entirely of his own making. The 26-year-old will be hoping it is the first of many in the colours of City.
Guardiola may well be frustrated with how side defended, but the home fans are certainly getting their monies worth: they have already cheered 16 goals in just three games at the Etihad this season.
MAN OF THE MATCH - Kevin De Bruyne (Manchester City)
Tonight will live long in the memory of Grealish, who was excellent and how he linked up with Bernardo Silva was a joy to watch, but De Bruyne was a class above with another fine attacking performance. With Chelsea and PSG on the horizon, his return to full fitness is a huge boost for City.
Manchester City: Ederson 6, Cancelo 8, Dias 7, Ake 6, Zinchenko 7, Rodri 7, Silva 8, De Bruyne 9, Mahrez 8, Torres 7, Grealish 8.. subs: Sterling 5, Foden 5, Gundogan 5, Fernandinho 5, Jesus N/A.
RB Leipzig: Gulacsi 5, Mukiele 5, Klostermann 5, Orban 6, Angelino 5, Laimer 5, Adams 6, Nkunku 8, Olmo 7, Forsberg 7, Silva 6.. subs: Brobbey 5, Gvardiol N/A, Haidara 5, Poulsen 5, Szoboszlai 5.
42' - GOAL! Manchester City 2-1 RB Leipzig (Christopher Nkunku): After a couple of warnings, RB Leipzig are back in the game! Forsberg's cross picks out Miekele at the back post, he nods it into the path of Nkunku, who reacts quickest and halves the deficit.
45'+1 - GOAL! Manchester City 3-1 RB Leipzig (Riyad Mahrez, penalty): A fantastic spot-kick from Mahrez. He sticks it into the top corner and City's two-goal advantage is restored just before half-time.
51' - GOAL! Manchester City 3-2 RB Leipzig (Christopher Nkunku): It's game on once more! Dr Bruyne trips over the referee in the middle of the pitch and that allows Olmo to run into space. He chips a cross to the near post where Nkunku runs in between two City defenders and heads past Ederson!
55' - GOAL! Manchester City 4-2 RB Leipzig (Jack Grealish): Grealish scores on his Champions League debut! The £100m man collects the ball on the left and carves inside, dropping a shoulder to create the space for a shot before curling it into the far corner.
73' - GOAL! Manchester City 4-3 RB Leipzig (Christopher Nkunku): A hat-trick for Nkunku! It's another fine goal from Nkunku that hands the visitors another lifeline! Poulson is the provider and the Leipzig striker makes no mistake with a cool, calm finish.
75' - GOAL! Manchester 5-3 RB Leipzig (Joao Cancelo): What a game this is turning out to be! Cancelo restores City's two-goal advantage with a sublime strike from all of 20 yards!
79' - Red card! Just when you thought you'd had your lot for tonight Angelino is then shown his marching orders against his former club for a second bookable offence.
85' - GOAL! Manchester 6-3 RB Leipzig (Gabriel Jesus): Just minutes after coming on, Jesus has the ball in the back of the net in what is his 200th appearance for the club. Leipzig fail to clear from a corner, the ball breaks kindly for the Brazilian and he applies the finish. There's a lengthy VAR check for offside, but it's going to count.
- Jack Grealish is the first Englishman to both score and assist on his UEFA Champions League debut since Wayne Rooney versus Fenerbahçe in September 2004.
- Riyad Mahrez has scored five goals in his last five UEFA Champions League appearances, one more than he had netted in his previous 29 in the competition (4).
- Christopher Nkunku, who is the first RB Leipzig player to score a UEFA Champions League hat-trick, is only the second player to score one against Man City in the competition after Lionel Messi in October 2016.
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