PSG suffered a rare league loss on Monday (AEST), upstaged by rival Monaco 3-1 at the Stade Louis II.

The result meant PSG dropped to fifth in the standings, having opened the season with back-to-back wins.

"We started well with two good chances, but then Monaco scored with their first attack of the game, and they're a side that know how to control a lead," Emery said. "They are very solid in defence, and we lost too many balls. In the second half, we came back to 2-1 and had chances to equalise, but then came that counter-attack.

"After the third goal, the match was over.

"It's an experience for the future. I have confidence in the team. The players that played earned that right. I made changes to have more control of the game. We were tactically a little unbalanced."

PSG struggled from the outset, after Joao Moutinho gave Monaco a 13th-minute lead, and it got worse on the stroke of half-time as Fabinho converted a penalty.

Embattled striker Edinson Cavani gave PSG some hope just past the hour-mark but a Serge Aurier own goal with 10 minutes remaining extinguished any chances of a comeback in Monaco.

"I think Monaco were the better team tonight. They deserved their win," PSG midfielder Thiago Motta said. "Every defeat is hard to accept, this one especially, because like us, Monaco are hoping to play for the title.

"We will bounce back. We'll look at the match again and analyse the positives and the negatives."