PSG coach Laurent Blanc was relieved to see his side progress into the Coupe de la Ligue quarter-finals after a narrow 1-0 win over Saint-Etienne.
Second-half substitute Edinson Cavani scored the only goal of the game on 86 minutes to seal PSG's progression into the next round.
Blanc praised his tired side's performance despite the fatigue of playing eight games in just over three weeks.
"This is our eighth game in 23 or 24 days," Blanc said. "We play every three days. Physical and psychological fatigue exists.
"It is a crazy schedule. My players are not machines. It was a typical cup match.
"We never gave up, and I still had a few weapons on the bench, which allowed us to win the game.
"At half-time, I told them [their performance] was insufficient, but we must also understand that the rate is a bit high for them."
Blanc admitted he chose to rest Javier Pastore despite getting through training on Tuesday.
"Pastore trained yesterday but he did not feel very good, so we chose to rest him again," Blanc said.
With such a heavy run of games with PSG still chasing a potential quadruple in Ligue 1, the Champions League, Coupe de la Ligue and Coupe de France, Blanc admitted such precaution was necessary at times, but warned rivals he would always play to win.
"We are defending champions and we will not sell our titles. We will play to win the Coupe de France and the Coupe de la Ligue, even though we clearly have larger goals," Blanc said.