France had already lost to Italy in their group and were staring in the face a 24-point deficit against the mighty Serbia. But Abdou Ndiaye's team did not roll over.
Instead, the French shut down the Serb offence and one point after another came back to upset Serbia by seven points.
France have not lost since then, entering their semi-final showdown against Spain at the U20 European Championship for Women with a five-game winning streak.
"That Serbia game was crazy. But it also was very important for my team to build their mental character," Ndiaye said of France's second half performance in the Preliminary Round.
"The way we played defense in the second half really helped us go on in this tournament. The next games against Latvia, Turkey and Czech Republic were all very tight. And we had that mental toughness to play hard."
Ndiaye admits that he has continued to mention the Serbia game to his players throughout the rest of the tournament.
"That's right. That was our character builder. The Serbian team has a lot of talent - some great players.
Our defence against Serbia gave us a lot of confidence to believe in ourselves and play together."
After beating Serbia by seven points, Ndiaye's team have shown a toughness to win close games - beating Latvia by four points, Turkey by eight and the Czech Republic by seven to take top honours in the Qualifying Round Group F.
Next up for the French is a semi-final date in Pescara with defending champions Spain, who lost to Russia on Thursday for their first defeat of the tournament.
Ndiaye expects a highly intense game.
"Spain can run the ball very quickly and pressure the ball on defence. We need to control their aggressiveness and the three-point stripe," said the coach.
The French are dealing with an injury concern however as shooting guard Sarah Michel is fighting a foot issue from the game against Turkey on Wednesday. She came into that game averaging 13 points a contest and hit four three-pointers against both Germany and Serbia. But Michel played just two minutes against the Czechs on Thursday.
"Sarah is very important in our play because she is very creative. She can play a bit inside and is a very good passer as well. She's a complete player," Ndiaye said.
"We don't know yet. Maybe I can use her some time on the floor against Spain."
Regardless how much Michel plays, the French hope to use their excellent low post players.
"It is one of our strengths definitely - the inside play. That has been our style of play until now. It's important for us to use our physicalness inside to control the tempo of play," said Ndiaye - referring to the play of Marielle Amant and Ana Cata-Chitiga.
But the coach doesn'tt just want to throw the ball into the post the whole game, grinning when he say: "We need to run too. And we can. We have the athletes."
Not only do they have the athletes to beat France and reach Sunday's final, but Ndiaye's team also have the confidence since the comeback against Serbia.