Venus Williams has been knocked out in the first round of the French Open for the third straight year, losing 6-4, 6-4 to Anna Karolina Schmiedlova.
The 40-year-old American is 0-3 in Grand Slams this year following first-round exits at the Australian Open and the U.S. Open.
Since the start of 2018, the seven-time Grand Slam champion has lost in the first round in seven of the past 11 major tournaments.
There were only a handful of spectators watching their match in chilly conditions on Court Simone Mathieu.
Williams, who lost the 2002 final to her younger sister Serena, was deep in trouble at 4-1 down in the second set. She fought back well before Schmiedlova clinched the match on serve, on her third match point, with a forehand winner down the line.
The Slovakian next faces 10th-seeded Victoria Azarenka, the U.S. Open runner-up.
Sebastian Korda, a qualifier whose father, Petr, won the 1998 Australian Open and was the runner-up at the 1992 French Open, has the first main-draw Grand Slam match win of his career.
The 20-year-old Korda beat Andreas Seppi of Italy 6-2, 4-6, 6-3, 6-3. Korda now faces another American, 21st-seeded John Isner.
Isner advanced by beating Elliot Benchetrit 6-4, 6-1, 6-3.