World number 361 Lois Boisson pulled off the biggest shock of this year's French Open with a stunning fourth-round victory against third seed Jessica Pegula.

The French player, given a wildcard into the main draw after tearing an anterior cruciate ligament in her knee last year, came through 3-6 6-4 6-4 against the US Open runner-up.

Boisson is making her debut in the main draw of a Grand Slam and had never played an opponent ranked in the world's top 50 before this week.

The 22-year-old had to stave off four break points as she served for the match at 5-4 in the third set before sealing victory with a thumping forehand winner.

Boisson was serenaded by chants of "Lois!" from the packed crowd on Court Philippe Chatrier as the moment sank in.

"I'm not sure what to say. Playing on this court, with this atmosphere, was amazing," she said.

"I gave my all and in the end I won, which is just incredible. I hope I'm going to win it all!"

She will play sixth seed Mirra Andreeva for a place in the semi-finals in Paris.

Things looked very different for Boisson 12 months ago.

After a successful series of performances on the third rung of the women's tennis tour, Boisson was given a wildcard for her home Grand Slam.

However, a week before the clay-court tournament began, Boisson tore the ACL in her left knee. She was unable to bring herself to watch last year's French Open and subsequently missed nine months of the season.

To speed up her recovery, Boisson did neurovisual training, which included sight tests, buzzer reaction tests and using virtual reality headsets to keep her reactions sharp.

She made her WTA Tour return at April's Rouen Open against Harriet Dart, where the Briton apologised for asking the umpire to tell her opponent to put on deodorant.

Boisson later made light of the issue, posting an edited photo of her holding some deodorant and telling toiletries company Dove that they "apparently need a collab".

Able to use the wildcard that injury denied her last year, Boisson beat 24th seed Elise Mertens in her opening match and overcame a second-set 'bagel' to beat compatriot Elsa Jacquemot in the third round.

A tattoo of the word 'resilience' on Boisson's right elbow is there to remind her that the hard work is worth it - and victory over Pegula is conclusive proof of that.

Outplayed and overawed in the first set, a superb backhand winner gave the Frenchwoman a crucial break in the second set.

After serving out to love, Boisson went a quick break up in the third before Pegula hit back.

However, at 4-4 Pegula again blinked first. Boisson broke and served out the match by saving break points with a mix of deft touch and devastating power.

She let out a roar of celebration as she secured victory and stood in the middle of the court with her arms aloft to soak in the atmosphere.

Boisson is the lowest-ranked player to reach the French Open fourth round since Serena Williams, who was then world number 451 as she made her return from maternity leave, in 2018.

She is also the lowest-ranked player to reach a major quarter-final since world number 418 Kaia Kanepi at the 2017 US Open.