PSG boss Thomas Tuchel has labelled his side's Coupe de France success as an "expensive victory" after Kylian Mbappe hobbled off.
The Parisians secured a 1-0 victory over Saint-Etienne thanks to Neymar's first-half strike.
But Mbappe was forced off in the opening 45 with what looked like a worrying injury after a nasty tackle from Loic Perrin
The Saint-Etienne man was sent-off but the Frenchman ended the evening on crutches.
After the contest Tuchel told Eurosport: "I have no news at the moment. Everyone would be worried after seeing the images of the injury. Of course, I'm worried."
PSG have secured the league and cup double once again but have hopes to finally ending their Champions League hoodoo.
The Parisians haven't reached the last four since the Qataris arrived but are in the quarter-finals of the competition.
They have been handed a very appealing draw and will face Italian side Atlanta before a possible semi-final game against either RB Leipzig or Atletico Madrid.
PSG though have hardly played in recent months after the early conclusion to the French season.
Their cup final win was their first game since March and Tuchel admits there is plenty they can improve on.
"Yes, we won. In a final, that's most important. It was complicated for several reasons," The German added.
“There are many things to improve and analyse. That's good. But it's an expensive victory.
“In the last three matches against Saint Etienne, they always have a red card in the first 30 minutes. And I'm not telling you what is said in the locker room before. And in addition, we are the ones who had three yellow cards.
"It was hard despite the numerical superiority. It was the first competitive match [since the shutdown], but we had a lot to lose. We were the big favourites.
"We had opportunities to score the second and I remembered last year when we lost after leading 2-0.
"The satisfaction remains to have won. We did not concede a goal and we did not get angry even if we were not at our best”
