Messi completed a sensational free transfer from Barcelona to PSG in August, with the French club uniting the Argentine, Brazilian star Neymar and French World Cup winner Mbappe up front
Pep Guardiola says he does not know how to stop the deadly attacking trident of Lionel Messi, Kylian Mbappe and Neymar as he prepares for Tuesday's blockbuster Champions League clash at Paris Saint-Germain.
The match is a repeat of last season's semi-final, which City won 4-1 on aggregate to reach their first Champions League final, which they lost to Chelsea.
Messi completed a sensational free transfer from Barcelona to PSG in August, with the French club uniting the Argentine, Brazilian star Neymar and French World Cup winner Mbappe up front.
Messi scored a record 672 goals in 778 games for Barcelona, winning two Champions League titles under Guardiola as well as several domestic trophies.
"With this amount of quality, I don't know what we should do to stop them -- they are so good," the City boss said on Monday.
"This amount of talent, all together to be controlled, is so difficult. You have to defend well when we don't have the ball, but it's difficult.
"They are exceptional players, everybody knows it."
Guardiola has bitter experience of facing Messi and Neymar from when he was manager at Bayern Munich -- the two players scored five goals between them to dump his team out at the Champions League semi-finals in 2015.
The City boss believes PSG's star-studded front line can match that of Barcelona's in 2015 -- which also included Luis Suarez -- and Liverpool's front three of Mohamed Salah, Sadio Mane and Roberto Firmino.
"They have the quality (to match)," he said. "They have exceptional players and a good organisation and I think the manager (Mauricio Pochettino) can do it.
"We know exactly how difficult it (PSG's attack) is -- maybe it's the most difficult one.
"We are going to try and do our game, knowing how good they are individually and collectively."
Manchester City top Group A after sweeping aside Leipzig 6-3 in their Champions League opener and are second in the Premier League after Saturday's 1-0 win at Chelsea ahead of Monday's game between Crystal Palace and Brighton.
PSG are two points behind City after an opening 1-1 draw against Club Brugge but top France's Ligue 1 after winning all eight of their league fixtures so far.