PARIS — A French Open already missing Serena Williams and Maria Sharapova is now without No. 1-ranked Angelique Kerber, too, lending even more of a feeling that the women’s championship is anyone’s to win.

Kerber has not been playing at all like one of the best at what she does, 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 replaced Williams atop the WTA rankings this month, was gone from Roland Garros by lunchtime on Day 1, putting up little resistance in a 6-2, 6-2 loss to 40th-ranked Ekaterina Makarova of Russia. It’s the latest in a string of early exits for Kerber, who reached her first three major finals in 2016.

“This year, I mean, the expectations are much bigger, especially in the big tournaments and the Grand Slams. And the expectations are also, from me, really big, of course, because I know what I can do, what I did last year,” Kerber said. “But right now, I think that I have to find myself again.”

Other significant results as the year’s second Grand Slam tournament began: Two-time Wimbledon champion Petra Kvitova played – and won – her first match since being stabbed by an intruder at her home in December; Venus Williams began her 20th appearance at Roland Garros with a victory; and Rio Olympics gold medalist Monica Puig eliminated 2015 U.S. Open runner-up Roberta Vinci, 6-3, 3-6, 6-2.

Makarova’s take when informed of the history made by her victory?

“Well,” she said, “that’s unbelievable.”

Although maybe not, considering how Kerber has fared lately.

Her Australian Open and U.S. Open titles and Wimbledon runner-up finish seem a bit in the distance now. The German has a 19-13 record this season and has lost four of her last six matches.

“If you are losing, it’s always tough to (enjoy) the game,” Kerber said. “I mean, I know in the last years I had always up and downs, and right now, of course, I’m … down.”

Add in that 23-time major champion Serena Williams is pregnant and won’t play until next season, and five-time major champion Sharapova was refused a wild card in Paris as she returns from a 15-month doping suspension, and the rest of the field might have more reason than usual to believe in the chance to claim a Grand Slam trophy.

“That’s the beauty of our sport right now: Anybody can win and everybody’s really good,” said Shelby Rogers, an American who beat Marina Erakovic of New Zealand 7-6 (4), 6-4 on a steamy day when the temperature touched 90 degrees.

“I like playing at this time for women’s tennis. It’s kind of – I don’t want to say open, because everyone’s really good, but – very competitive,” Rogers said, “and there’s not like that dominating force.”

Kerber’s strokes were off against Makarova, who has reached two major semifinals but has never been past the fourth round in Paris. Makarova pointed out she never had played a singles match in the tournament’s main stadium (she was the 2013 French Open women’s doubles champion).

In the preceding match on Court Philippe Chatrier, Kvitova’s eyes welled with tears at the end of her 6-3, 6-2 win against 86th-ranked Julia Boserup of the United States.

“I think it doesn’t really matter how I played, but I won,” Kvitova said.

Only in recent days did Kvitova decide to enter the French Open.

“I saw her in the locker room a couple of days ago,” said Bethanie Mattek-Sands, an American qualifier who will face Kvitova in the second round after beating Evgeniya Rodina 7-5, 6-2. “Gave her a big hug. It’s great to see her come back.”

The only seeded men’s player to lose Sunday was No. 26 Gilles Muller, who fell 7-6 (4), 6-7 (2), 6-2, 6-2 to Guillermo Garcia-Lopez. No. 6 Dominic Thiem and No. 11 Grigor Dimitrov advanced in straight sets.