Lois Boisson

Boisson made her WTA Tour debut at the 2021 WTA Lyon Open, having received a wildcard into the doubles main draw, partnering Juline Fayard.

Following three titles on the ITF Circuit earlier in the year, Boisson won her first WTA 125 title in Saint-Malo, defeating Chloé Paquet in three sets in the final. She entered the top 200 as a result. She was slated to receive a wildcard for her major main-draw debut at the French Open but missed the event, after injuring her left knee, tearing her ACL a week before Roland Garros, at the 2024 Trophée Clarins.

In May, ranked No. 361, on her Grand Slam tournament debut at the 2025 French Open, Boisson reached a semifinal for the first time, recording her first major wins, as a wildcard, defeating 24th seed Elise Mertens, Anhelina Kalinina, fellow wildcard Elsa Jacquemot, world No. 3, Jessica Pegula, and world No. 6 and former semifinalist, Mirra Andreeva. Boisson was the first woman to make the quarterfinals in her major main-draw debut since Carla Suárez Navarro made the last eight in 2008 as a qualifier. Boisson became the lowest-ranked quarterfinalist and semifinalist at Roland Garros in the last 40 years, and the lowest quarterfinalist at any major event since 2017 (No. 418 Kanepi at the US Open). She became the first woman in 35 years to reach the semifinals at their first major since Jennifer Capriati in 1990, and the first Frenchwoman since Marion Bartoli in 2011, into the Roland Garros semifinals. Her run was ended by eventual champion and second seed Coco Gauff. As a result, she reached world No. 65, moving nearly 300 positions up and entering the top 100 in the singles rankings with the biggest leap of the 21st century. She became the French No. 1 player on 9 June 2025.

In June, Boisson requested a wildcard into the main draw of Wimbledon, but was turned down. with tournament organisers stating "wildcards are usually offered on the basis of past performance at Wimbledon or to increase British interest". Instead, using her protected ranking, she entered qualifying as the top seed but was defeated in the first round by Canadian Carson Branstine in three sets.

In July, Boisson won her maiden title on the WTA Tour at the Hamburg Open by defeating second seed Dayana Yastremska in the semifinals and defending champion Anna Bondár in the final. She entered the top 50 as a result.