World number one Naomi Osaka avoided a premature end to her bid for a third straight Grand Slam title by coming from behind to reach the French Open second round.
Osaka, 21, twice had to stop Slovakia's Anna Karolina Schmiedlova serving out the match before winning 0-6 7-6 (7-4) 6-1 at Roland Garros in Paris.
Schmiedlova, ranked 90th in the world, made very few errors until victory was in sight, but the pressure of a career-best win told as Japan's Osaka fought back.
The US Open and Australian Open champion, playing in her first Grand Slam as the top seed, will face two-time Grand Slam champion Victoria Azarenka of Belarus in the second round.