World number one Ashleigh Barty came through an injury scare to avoid a shock in the French Open first round against American Bernarda Pera.

However, the Australian recovered to beat world number 70 Pera 6-4 3-6 6-2.

Elsewhere, fifth seed Elina Svitolina survived a second-set fright to beat teenage debutant Oceane Babel 6-2 7-5.

With second seed Naomi Osaka withdrawing from the tournament after her refusal to speak to the post-match media, Barty is guaranteed to remain top of the world rankings regardless of results at Roland Garros.

Venus Williams and American teenager Coco Gauff are among those also in first-round action later on Tuesday.

Svitolina tested by teen debutant Babel

Earlier on Court Philippe Chatrier, world number six Svitolina fought back from a break down in the second set to bring 17-year-old Paris native Babel's first senior Grand Slam appearance to an early end.

After losing a one-sided opening set, Babel threatened a fightback as she led 5-2 in the second but Svitolina won five successive games to progress.

Svitolina will meet Ann Li in round two after the American thrashed Russia's Margarita Gasparyan 6-0 6-1.

The Ukrainian was made to work hard for her victory by Babel, who was playing an opponent ranked inside the world's top 150 for the first time.

"It's a first time for her to play here in the main draw of the Grand Slam and to face the sixth player in the world it's extremely tough," Svitolina said.

"I think she dealt very well with it and she went for her shots in the second set and made life very difficult for me."

Australian Open finalist Jennifer Brady beat Anastasija Sevastova 6-3 6-3, while Greek 17th seed Maria Sakkari defeated Ukraine's Katarina Zavatska 6-4 6-1.