Boisson, a wildcard who has never played in the main draw of a grand slam before, pulled off her second scarcely believable upset this week to reach the semi-finals at Roland Garros.
Boisson dropped to the clay with her hands over her eyes in emotional scenes before cupping her ear to the crowd on a packed, raucous Court Philippe-Chatrier.
It was all too much for Russian teenager Andreeva, who had two set points in the first but suffered a complete meltdown in the second after squandering a 3-0 lead.
She told the crowd to "shut up", received a code violation for whacking a ball into the stands, burst into tears and forced her mother Raisa to leave her box.
Roared on under the roof of Chatrier, Boisson won the final six games of the match
Boisson, who suffered a career-threatening ACL injury before what was supposed to be her debut here last year, will at least break into the world's top 70 next week.
Appropriately, on her right arm, she has a simple tattoo: RESILIENCE.
But she is playing like a top-10 player. She has now beaten the third seed, Jessica Pegula, and the sixth. Second seed Coco Gauff awaits on Thursday for a place in the final.
"It's incredible. Thank you for supporting me like this — I have no words," Boisson told a delirious home crowd.
Later, the daughter of a former professional basketball player told a press conference: "For sure, every tennis player dreams of winning a Slam - and for a French player, Roland Garros even more so. I'll go for it because my dream is to win the final, not the semi-final.
Earlier, Gauff huffed and puffed to a 6-7 (8-6) 6-4 6-1 victory against fellow American Madison Keys in a error-strewn match both players will want to forget quickly.
More than half of Gauff's points came from the Australian Open champion's mistakes and the world No.2 got away with a total of 10 double faults. Altogether there were over a 100 errors.
The 21-year-old will need to make dramatic adjustments when she faces Boisson for a place in Sunday's final.
Keys, who was looking to reach the last four at Roland Garros for the second time after 2018, bowed out with her 60th unforced error to end a forgettable contest.
"I'm happy to get through this match today, I have a lot more work to do, I'll be ready tomorrow," Gauff said.
Gauff, who reached the final here in 2022, is the youngest woman to claim 25 main-draw wins at Roland Garros since Martina Hingis (1995-2000).
While the quality was patchy at best, the drama was undeniable, with momentum swinging wildly. In the end, Keys edged the tiebreaker in the first set as Gauff double-faulted three times.
Things did not get better in the second set. "So many unforced errors," Gauff said on court, in one of the understatements of the season.
She levelled the contest as Keys looked out of sorts and cantered through the decider.
With PA
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