Serena Williams hits a backhand to Emma Raducanu during the...

Serena Williams hits a backhand to Emma Raducanu during the Western & Southern Open on Tuesday in Mason, Ohio. Credit: AP/Aaron Doster

MASON, Ohio  — The second stop on Serena Williams’ farewell tour was a short one.

The 40-year-old Williams fell to 0-2 in matches since announcing “the countdown has begun” on her career, losing 6-4, 6-0 to U.S. Open champion Emma Raducanu in the first round of the Western & Southern Open on Tuesday night.

Williams said last week in a Vogue magazine essay and an Instagram post that her career was winding down, although she did not explicitly say the U.S. Open, which begins Aug. 29 in New York, would be her last tournament.

The Western & Southern Open was the second U.S. Open tuneup for Williams, and the next time she takes the court will be at Flushing Meadows. She lost to Belinda Bencic in straight sets last week in Toronto. A day before the announcement, Williams beat Nuria Parrizas-Diaz for her first match win since the 2021 French Open.

Williams is a 23-time Grand Slam champion, most recently in 2017 at the Australian Open, when she was pregnant with daughter Olympia. She said wanting to expand her family was a big reason she plans to step away.

Raducanu, ranked No. 19 in the world, was sharp as she dispatched Williams — and quieted the vocally pro-Williams crowd — in 1 hour, 5 minutes.

Fans cheered heartily when Williams was introduced, and again when she won her first point on a Raducanu error in the second game. Williams yelled in frustration when she double-faulted and screamed even louder and pumped her fist when she won the third game of the first set.

Down 2-0 in the first set, she fought back within 4-3 and then 5-4, but Raducanu closed out the set at love. Raducanu rolled from there, with Williams looking frustrated and even resigned near the end.

Her later-career inconsistency was on display. The players thrilled the crowd with an exciting rally in the fifth game of the second set, won by Williams with a forehand volley. But she double-faulted on the next point on the way to being broken.

She briskly left the court after the match, waving to the crowd as she exited.

Raducanu, a 19-year-old from Britain, faces veteran Victoria Azarenka in Wednesday's second round. She has not won a title since her out-of-nowhere triumph at the U.S. Open last year.

Earlier Tuesday, four-time Grand Slam champion Naomi Osaka was eliminated by Shuai Zhang, 6-4, 7-5.

The tournament lost another big name, Coco Gauff, when she retired from her match against qualifier Marie Bouzkova with a left ankle injury. Gauff had her ankle taped after the first set and dropped out after the first game of the second set.

Karolina Pliskova advanced with a 7-5, 6-1 win over Venus  Williams.

Rafael Nadal, sidelined since withdrawing from Wimbledon with an abdominal tear, practiced before a large crowd. The 22-time Grand Slam champion is scheduled to play a second-round match on Wednesday.

In a men’s first-round match, Wimbledon finalist Nick Kyrgios beat Alejandro Davidovich Fokina 7-5, 

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