Dominic Thiem was pushed to the limit by a gallant Alexander Bublik before advancing to the third round.
In the first match of the day on Court Philippe-Chatrier, the No.4 seed trailed 5-2 in the fourth set - and faced two set points - before recovering to win 6-3, 6-7(6), 6-3, 7-5.
Shortly after that, across on Court Suzanne-Lenglen, women's top seed Naomi Osaka staged a gritty comeback to subdue former world No.1 Victoria Azarenka.