Thomas Tuchel says PSG were at their worst against Manchester United on Tuesday.
Last season's finalists were outplayed against the visiting Red Devils, who found a deserved late winner through Marcus Rashford.
And Tuchel was left unimpressed by his players when speaking after the game.
"In the first half, we were simply not on the pitch," Tuchel told beIN SPORTS. "It was not our level.
"I don't know why, but I can just say that it was not our level, in moving the ball, in possession, in counter-attacking, in challenges, in intensity.
"By far, one of our worst games, one of our worst first halves.
"The good news was that it could not be worse. Okay, we were down 1-0, it is easy to play better in the second half and we had to step up, it was clear," Tuchel added after star forward Neymar failed to score in four consecutive Champions League appearances for the first time since November 2013.
"We tried to do some tactical changes because of the injury of Idrissa Gueye, we tried to bring on one more offensive guy, which was a risk that we paid for at the end also. It was like this today.
"From the start until the end it felt like we were never at our highest level, and we weren't really into the match like was absolutely necessary on this level."
