PSG boss Christophe Galtier said he cannot understand why a section of the club's fans are booing Messi.
"Leo Messi tried very hard," Galtier said after Sunday's game. "It is not just about Messi and Kylian Mbappe. There were some technical mistakes in his [Messi's] link-up play, but I think the whistles are hard to listen to because Leo Messi gives so much. He has got goals and assists in 2023, but it is also down to his teammates in terms of doing more to create more danger in the opposition penalty box."
Messi, who last week surpassed 100 international goals with Argentina, has not found the back of the net for PSG in the past four games, including the 2-0 defeat at Bayern Munich that saw his side exit the Champions League in the round of 16.
Asked if he had considered dropping Messi from the starting lineup, Galtier said: "When it is a difficult period and you need to turn a situation around and score goals, Leo Messi is a decisive player who is capable of coming up with a moment of magic that can be decisive for scoring goals. He has scored goals in 2023, he has got assists. I have never thought about taking him off or not playing him. He is an important player in our attacking line-up."
Barca forward Robert Lewandowski has told ESPN he hopes Messi joins him at Spotify Camp Nou next season.
"That would be great if he's coming," the Poland striker said on Saturday. "I know that there are a lot of rumours now, but in the end we have to be patient and we [will] see what's going on.
"Of course, Barcelona and the place for Lionel Messi belong, and I hope that something happens. But now we have to be focused on this season and what we can achieve this season with the team."
Messi is in his second campaign at PSG and has contributed 13 goals and 13 assists 24 league appearances. He is under contract with PSG until the end of the season.