Angelique Kerber became the first top seed in the women's draw to lose in the opening round at Roland Garros in the Open era.
The German, who also lost in round one last year, has had a miserable season and is not a fan of clay so the 6-2 6-2 loss to Ekaterina Makarovacame as no real surprise.
Russian Makarova, ranked 40, won five of the first six games and, although she came under more pressure in the second set, she kept Kerber at arm's length.
The top seed dropped serve six times and made 25 unforced errors in a match that lasted an hour and 22 minutes.
Makarova, who has made the fourth round here twice, was a tough opponent for a player who does not like clay and has reached just one WTA Tour final all year.
It is a second consecutive first-round loss at Roland Garros for Kerber, who won the Australian Open and US Open titles last year and reached the Wimbledon final.
She said: "This year, the expectations are much bigger, especially in the big tournaments and the grand slams. And the expectations are also from me really big because I know what I can do, what I did last year.
"But right now I think that I have to find to myself again and just try to forget the clay court season as soon as possible, and then reset and start from the grass courts again."