Manchester: Manchester City, last season's Champions League runners-up, crushed RB Leipzig 6-3 in a thrilling Group A game on Wednesday as Christopher Nkunku scored a hat-trick for the German side.
It was a hugely entertaining match at the Etihad Stadium and although City manager Guardiola will be happy with the three points he will be concerned about the spaces his team left for the German side to exploit on the break.
Nkunku became only the fourth player to score a Champions League treble and end up on the losing side and he deserved his player of the match award as Leipzig showed real spirit to keep fighting back against City's impressive firepower.
Defender Nathan Ake put City ahead in the 16th minute with a header from a Jack Grealish corner and the hosts doubled the lead 12 minutes later when Kevin De Bruyne produced wonderful skill to leave three defenders for dead before his deep cross was headed into his own net by Leipzig defender Nordi Mukiele.
Leipzig got back in the game with a 42nd-minute header from Nkunku, only for City to restore their two-goal advantage on the stroke of half-time.
Lukas Klostermann was ruled to have handled after the referee went to the pitchside monitor to check the incident and Riyad Mahrez blasted home the spot-kick.
Leipzig were not deterred, though, and Nkunku reduced the deficit again in the 51st minute by heading in a cross from the excellent Spanish midfielder Dani Olmo.
Grealish then delivered a wonderful solo goal to mark his first European club appearance, collecting the ball on the left flank and jinking inside before giving Peter Gulacsi no chance with a curling shot into the far corner.
That was surely that, the City fans could be forgiven for thinking, but once again French forward Nkunku kept the game alive, completing his hat-trick with a crisp drive after being set up by Yussuf Poulsen.
Incredibly, City responded immediately with an unstoppable long-range drive from Portuguese full back Joao Cancelo and any hopes the visitors had of a comeback ended when they went down to 10 men when former City full back Angelino was sent off in the 79th minute.
Substitute Gabriel Jesus added the sixth from close range five minutes from time and the home crowd were delighted with the display of Grealish, in front of his England manager Gareth Southgate.
City lead the group on three points after Paris St Germain (PSG) were held to a 1-1 draw at Club Brugge in their opener.
Lionel Messi failed to provide PSG with any sparkle as the Ligue 1 team's potent attacking trio lacked inspiration.
Making his first start for the French team, the Argentine forward hit the woodwork but was otherwise far from his brilliant best alongside the hugely disappointing Neymar and Kylian Mbappe, who set up Ander Herrera for PSG's first-half opener before being replaced injured after the break.
Brugge, who levelled before half-time through Hans Vanaken, were more aggressive and had the best chances against a PSG side lacking quality and defensive focus.