Upset: World No.1 Kerber suffers shock exit in Round I

Angelique Kerber has not been playing at all like someone ranked No. 1 this season, and on Sunday she became the first woman seeded No. 1 to lose in the French Open's first round in the professional era.

Kerber, who ended Serena Williams' stay atop the WTA rankings last year, was gone from Roland Garros by lunchtime on Day 1, putting up little resistance while being beaten 6-2, 6-2 by 40th-ranked Ekaterina Makarova of Russia.

"Well," Makarova said when informed of the history made by her victory, "that's unbelievable."

Kerber won the Australian Open and U.S. Open, and was the Wimbledon runner-up, in 2016, surging to the heights of tennis. But this year has been much more of a struggle: The German has a 19-13 record, losing 4 of her past 6 matches.

Her strokes were off all match against Makarova, who has reached two major semifinals but never been past the fourth round in Paris.

Makarova even pointed out that she never before had played a singles match in the tournament's main stadium (she was the 2013 French Open women's doubles champion).

Kerber had only four winners and 12 unforced errors in the first set and didn't even earn a break point until the last game, which Makarova won, anyway. Makarova then raced to a 3-0 lead in the second set.

Kerber showed some signs of getting into the match, smacking a cross-court forehand passing winner, leaning forward and yelling as she took a game to get within 3-1. But that was about it. In the last game, Kerber had seven break points but Makarova fought off each one before holding to win.

"It was really tough. She's a No. 1 and she's a great player and I knew that I have to win it; she's not going to miss it," Makarova said. "I was also fighting with my emotion."

In the preceding match on Court Philippe Chatrier, Petra Kvitova was back competing in a tournament, less than six months after a knife attack at her home.

Kvitova, a two-time Wimbledon champion, had very little trouble in her return, beating 86th-ranked Julia Boserup of the United States 6-3, 6-2 in 74 minutes.

"I think it doesn't really matter how I played, but I won," Kvitova said. "I won already, before." Indeed, just being there under a cloud-filled sky at Roland Garros was a victory for Kvitova, who needed surgery on her left hand the one she holds her racket with after being stabbed by an intruder in the Czech Republic in late December. She was undecided until late last week whether to even try to play in the French Open. "It's a pleasure to be here. I'm really glad that we made this decision that I'm going to play here," Kvitova told the crowd during an on-court interview.