Serena Williams celebrates after match point against Maria Sakkari of Greece (not pictured) to reach quarter finals of the 2020 US Open at USTA Billie Jean King National Tennis Center on Monday. Image Credit: USA Today

New York: Her breathing loud enough to hear in an empty Arthur Ashe Stadium, her third-set deficit a point from growing to 3-1 against someone who beat her less than two weeks earlier, Serena Williams scrambled to extend a 13-stroke exchange until her opponent netted a forehand.

``Keep fighting!’’ Williams exhorted herself.

Locked in a tough fourth-round match Monday, and without the benefit of a pro-American audience, Williams provided her own encouragement along the way to coming back and beating 15th-seeded Maria Sakkari of Greece 6-3, 6-7 (6), 6-3, reaching the quarterfinals in a 12th consecutive appearance at Flushing Meadows.

‘‘I feel like I’m pretty vocal with or without a crowd. ... I’m super passionate. This is my job. This is what I wake up to do. This is what I train to do, 365 days of the year,’’ said Williams, who moved a step closer to a record-tying 24th Grand Slam title.

‘‘Yeah, I’m always going to bring that fire and that passion,’’ she continued, ‘‘and that `Serena’ to the court.’’

When the match ended, after Williams collected six of the last seven games, she turned and yelled toward her husband, who stood at his front-row seat and yelled right back.

How tight was this contest? Sakkari produced more aces than Williams, 13-12, and more total winners, 35-30.

Williams was two points from victory at 6-all in the second-set tiebreaker, but faltered there, sending a backhand return long to give Sakkari her fifth set point, then pushing a forehand out.

This was a rematch from August 25, when Williams faded after building a lead and lost in three sets to Sakkari at the Western & Southern Open, a hard-court tournament usually held in Ohio but moved to the US Open site as part of a two-tournament ‘‘controlled environment’’ without spectators amid the coronavirus pandemic.

Second seed Dominic Thiem of Austria serves to Felix Auger-Aliassime of Canada on way to his fourth round win at the US Open tennis championships on Monday. Image Credit: AP

‘‘Of course I thought about (the loss), but ever so little, because it’s a completely different match, completely different scenario, completely different moment,’’ Williams said.

In the earlier one, Williams’ legs were cramping by the end, and she blamed herself for that situation, memorably declaring: ``I put myself in a bad situation. It’s like dating a guy that you know sucks.’’

Williams, who turns 39 in less than three weeks, will face unseeded Tsvetana Pironkova for a semifinal berth.

Playing in her first tournament in more than three years after taking time off to have a child, the 32-year-old Pironkova advanced with a 6-4, 7-6 (5), 6-3 victory over Alize Cornet.

No. 16 seed Elise Mertens knocked off second-seeded Sofia Kenin 6-3, 6-3 to reach the quarterfinals of the tournament for the second year in a row and deny the American a chance for back-to-back Grand Slam titles.

Kenin won the Australian Open and was trying to become the first with two straight Grand Slam titles since Naomi Osaka won the 2018 U.S. Open and the 2019 Australian Open.

Mertens will face Victoria Azarenka, who beat No. 20 Karolina Muchova 5-7, 6-1, 6-4 for her ninth straight win. Azarenka won the Western & Southern Open that was played in New York as an in-the-bubble warm-up for the U.S. Open.

Big chance for Thiem

In men’s action, where Novak Djokovic’s default on Sunday left zero past Grand Slam champions in the bracket, No. 2 seed Dominic Thiem moved into the quarterfinals by claiming a close first set and then running away with a 7-6 (4), 6-1, 6-1 win against No. 15 Felix Auger-Aliassime.

Thiem, a three-time major runner-up, now meets first-time Slam quarterfinalist Alex de Minaur, a 21-year-old Australian who eliminated Vasek Pospisil 7-6 (6), 6-3, 6-2.

Quarter-final draw

(x denotes seed):

Men’s singles


Pablo Carreno Busta (ESP x20) v Denis Shapovalov (CANx12)

Borna Coric (CRO x27) v Alex Zverev (GER x5)


Andrey Rublev (RUS x10) v Daniil Medvedev (RUS x3)

Alex de Minaur (AUS x21) v Dominic Thiem (AUT x2)

Women’s singles


Jennifer Brady (USA x28) v Yulia Putintseva (KAZ x23)

Naomi Osaka (JPN x4) v Shelby Rogers (USA)


Tsvetana Pironkova (BUL) v Serena Williams (USA x3)

Victoria Azarenka (BLR) v Elise Mertens (BEL x16)