Diacre, celebrating her 40th birthday, also became the first woman to coach in a game in the top two divisions of European football as she made her debut with Clermont Foot in their Ligue 2 match away to Brest.
Despite taking an early lead, her side conceded two second half goals to lose 2-1.
"We made two mistakes on the goals that we conceded, but we did some good things which are promising for the future," Diacre said.
"Brest were in charge of the game and we had to chase the ball too much.
"I'm still happy with my players because they gave so much," added Diacre, who was presented with flowers by Brest coach Alex Dupont before the game.
"I'm proud of their performance tonight. Clermont will have to be taken seriously this season."
Souleymane Sawadogo gave Clermont an eighth minute lead before Brest replied with goals from Bruno Grougi and Alexandre Alphonse after halftime.
Diacre, former captain of the France women's team, took over at the end of June following the surprise resignation of Portugal's Helena Costa.
Costa became the first female to be named coach of a men's team in the top two divisions of European soccer but quit before taking charge of a game, saying the club had hired players without her knowledge.
Clermont finished 14th in the 20-team table last season.
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