Serena Williams turns 40 in September. No one knows how many more French Open appearances she will make after this year’s tournament ended for her on Sunday.

Williams fell way behind and could not put together a comeback against a much younger and less-experienced opponent in the fourth round at Roland Garros, losing 6-3 7-5 to Elena Rybakina – who wasn’t even born when the American made her tournament debut in 1998.

Asked whether that might have been her last match at the clay-court major, Williams responded: “Yeah, I’m definitely not thinking about it at all.

“I’m definitely thinking just about other things, but not about that.”

Wimbledon – which Williams has won seven times – begins on June 28.

“I’m kind of excited to switch surfaces,” Williams said.

“Historically I have done pretty well on grass.”

Serena Williams on Centre Court at Wimbledon during the 2019 Grand Slam. Photo: Getty

She has won 23 grand slam singles titles to be agonisingly one shy of the all-time record in the professional era.

She is one of the sport’s greatest and most popular players, so it was quite a blow to the tournament, its TV partners and tennis fans to see her gone from the French Open field.

Williams has won the title at Roland Garros three times but hasn’t been past the fourth round in Paris since she was the runner-up in 2016.

Rybakina is a 21-year-old from Kazakhstan who is ranked 22nd.

This was just the seventh slam appearance and the first time she ever made it so much as past the second round.

“When I was small, of course, I was watching her matches on TV. So many grand slams,” Rybakina said.

Against Williams, whose right thigh carried a heavy tape job, Rybakina hit big, flat serves.

She dealt with, but managed to steady, her nerves. She even produced the occasional return winner off Williams’ speedy and spectacularly gifted serve, breaking her five times, including in the next-to-last game.

“I knew that the serve was going to be difficult for me to return. She’s powerful, but I was ready,” Rybakina said.

“Then, after few points, I felt… comfortable.”

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Since winning the 2017 Australian Open while pregnant for her most recent major singles title – Williams has four runner-up finishes at slams, most recently against Bianca Andreescu at the 2019 US Open.

Rybakina next will meet her doubles partner Anastasia Pavlyuchenkova with a semi-final berth on the line.

Pavlyuchenkova advanced with a 5-7 6-3 6-2 victory over two-time Australian Open champion Victoria Azarenka.

On the same side of the draw, Paula Badosa will face Tamara Zidansek in the last eight.

One of those four players will become a first-time grand slam finalist next weekend.