The French champions had a two-goal lead at half-time which evaporated as they shipped three goals after the break
Paris Saint-Germain head coach Thomas Tuchel was dismayed after watching his side throw away a two-goal lead in a “catastrophic” second half at Monaco.
The champions looked well on their way to three points in Friday’s Ligue 1 encounter at Stade Louis II, as Kylian Mbappe’s first-half double put them up 2-0 at half-time.
PSG could have been four goals up at the break, but Moise Kean and Mbappe had efforts ruled out by VAR for offside, which would ultimately prove costly.
Kevin Volland’s second-half brace and a late Cesc Fabregas penalty gave Monaco a stunning 3-2 comeback win, putting them into second place ahead of the weekend’s games.
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Speaking to Telefoot after the match, Tuchel lamented his side’s capitulation in their first loss since the second match of the season.
“Catastrophic? Yes, the second half,” Tuchel said. “We controlled the game, we scored two goals, and we could have scored two more. The third was onside. We had opportunities.
“In the second half, we didn’t have the same concentration. We weren’t serious enough. We didn’t recover the ball with the same quality, and we didn’t seriously defend. We are completely responsible for this defeat, when the match was almost over in our favour.
“They felt it was 3-0 or 4-0 when it was only 2-0. I have no explanation. I have to accept all the criticism, because we have completely stopped playing, and we haven’t done what is necessary to win.”
Catastrophic was also the word defender Presnel Kimpembe used to describe his side’s performance.
“We had a catastrophic second half, even unacceptable,” Kimpembe said. “We don’t have the right to have a half like that with the team we have.”
The last time PSG lost a Ligue 1 game after leading by two goals was back in January 2015, when they fell 4-2 to Bastia.
It was also the first time PSG had conceded at least two goals in a Ligue 1 match since they defeated Bordeaux 4-3 in February.
Tuchel’s side will be back in action on Tuesday when they face RB Leipzig in a Champions League match at Parc des Princes.