Kylian Mbappe suffered from muscle fatigue in Paris Saint-Germain's win at Lorient, says Christophe Galtier, who has eased fears over the attacker's fitness ahead of the World Cup.
Danilo Pereira's late header sent PSG five points clear at the top of Ligue 1 on Sunday, after in-form Terem Moffi had cancelled out Neymar's opener at the Stade du Moustoir.
However, Mbappe attracted attention by heading straight down the tunnel following his 85th-minute withdrawal.
France will already be without Paul Pogba and N'Golo Kante for their World Cup defence, while Karim Benzema has missed several of Real Madrid's fixtures during an injury-hit season, including the upcoming meeting with Rayo Vallecano.
Galtier, however, quashed concerns over Mbappe's condition after the win, telling Amazon Prime Video: "[It's] nothing serious. We saw the news about Karim, but nothing serious for Kylian.
"Kylian made an effort. It's much better to ask to go off than to take the risk of staying on the pitch, or being on the pitch and being totally absent."
In his post-match press conference, Galtier revealed Mbappe had been suffering from fatigue as a result of PSG's congested schedule.
"There is no alert in a specific area, it's fatigue linked to the sequence of matches," Galtier said. "The playing conditions were difficult.
"He also came out tired after Juventus on Wednesday. It's a very busy schedule, with a certain apprehension. Everyone is listening to their body in this pre-World Cup period. There can be a fear."
With PSG failing to meet their usual standards in their penultimate game before the World Cup break, Galtier believes the spectre of the tournament caused his side to play with "restraint".
"Automatically, the World Cup is in the minds of the players. It's hard for them to manage. There is always information that can make them doubt," Galtier said.
"You have the feeling of playing at 100 per cent, but today I saw a certain restraint, linked to fatigue, plus the announcement of the squads in a few days.
"We did a little less, we were a little fearful in duels, but fatigue also made it difficult in the second half."
PSG were without Lionel Messi against Lorient, though he is expected to return before the World Cup break.