Guardiola’s Manchester City side face the star-studded French outfit in their second Champions League Group A game at the Parc des Princes on Tuesday.
City memorably edged out PSG in a hard-fought two-legged semi-final last season but their summer signing of six-time world player of the year Messi makes them a tougher prospect this time.
Guardiola said: “What should we do? I don’t know. With this amount of quality I don’t know how to stop them, honestly. They’re so good.
“This amount of talent together – to control it is so difficult. We will try to defend well when we don’t have the ball and make them run when we have the ball.
“They’re exceptional players. All of them are so good individually. They can combine and connect with each other. We’re looking forward to playing the game.”
Messi has been a fitness doubt in the build-up to the glamour clash but returned to training on Monday after missing the last two games.
Guardiola is well aware of the havoc Messi can cause after their glory days together at Barcelona. Messi was the star player as Barca won the Champions League twice under Guardiola in 2009 and 2011.
The City manager said: “Messi speaks for himself on the pitch. I don’t have to add anything else.
“We’re fortunate to have seen him during these 15 or 16 years as a professional. What he’s done in his career is more than exceptional and hopefully tomorrow he can play for the benefit of the game.”
Messi left Barca in tears amid a financial crisis at the Catalan club in August.
Guardiola admits it was initially difficult to imagine him ever playing anywhere other than at the Nou Camp.
“It was a little bit of a surprise for everyone but it has happened and now everybody has accepted it,” he said. “A long time ago you could not imagine it but it’s happened.
“In football, life itself, you never know what is going to happen. The important thing is he will be happy in Paris.”
Guardiola feels Messi is one of the chief reasons why last season’s semi-final will have no bearing on the sides’ meetings this term.
He said: “That was last season. They are a fantastic team and it was a tight game, and now they have Messi.
“They are huge competitors and these are new games, a new competition. It’s the group stage, not the knockout. It’s different.
“We played a few days ago and that gives us positive energy but football is highs and lows and can change so quickly.
“Against PSG they were better in the first half in Paris. In Manchester we defended better than we expected and punished them on the counter.
“They have the talent and we have to do it as a team. We have to be compact, help each other and know we are going to suffer and have pain. It’s about how you handle the pain.”