New York (AFP)

Another standoff, but still a semifinal at stake: Serena Williams qualified Wednesday for the 13th time in her career for the last four of the US Open where she is chasing a record 24th Grand Slam title.

She will face Thursday in half Victoria Azarenka (27th) or Elise Mertens (18th) who will decide in the evening.

Williams, who won 4-6, 6-3, 6-2, hasn't lost before the US Open halves since 2007.

But on Wednesday, against the Bulgarian Tsvetana Pironkova, who was returning to competition after a three-year break, the American started her match with difficulty.

"I was tired. I had heavy legs, I lacked energy", she admitted after this rare duel of mothers.

So much so that Pironkova, varying her strokes enormously and even rewarding her opponent with forehands nabbed, greatly hampered the 8th world.

Completely liberated, uninhibited and without any apparent pressure, Pironkova won the first round and followed by a break from the start of the second set.

But Serena then became Serena again and she made Serena: the cries of rage became howls and she gradually came back into the game, breaking immediately.

"I continue to fight, I never give up and I move forward ..." she said with satisfaction.

And while Pironkova continued to go for it, Williams turned the game around.

Still, at almost 39 years old (she will celebrate them on September 26), Serena Williams offered herself a new grueling battle after beating, with the same type of difficulties, Maria Sakkari 6-3, 6-7 (6/8 ), 6-3 in the round of 16 and Sloane Stephens 2-6, 6-2, 6-2 in the third round.

- "Better start" -

But she will have to go to her semi-final on Thursday.

"Yes, the good news is that I am able to continue the games again, but I will have to find a way to start better," she said.

In the men's table, the semi-final at the bottom of the table must be determined on Wednesday, significantly higher than the top, especially since the disqualification of Novak Djokovic.

The two most fit players since the start of the tournament face off during the day in a fratricidal duel between Russians Daniil Medvedev (5th) and Andrey Rublev (14th).

The first, a magnificent finalist last year against Rafael Nadal, has yet to give up a single set of the tournament and has swept away all his opponents without breaking a sweat.

He passes his first real test against his compatriot, whom he has known on the courts since their young years.

Rublev, in explosive tennis when Medvedev's is more thoughtful, took his revenge in the previous round against Matteo Berrettini, another hitter, who had eliminated him last year in the 8th.

The final men's quarter will oppose Dominic Thiem (3rd) to Alex de Minaur (28th) at the end of the program.

The Austrian, finalist at Roland Garros in 2018 and 2019 and at the Australian Open 2020, hopes to finally materialize.

The 2020 US Open is bound to have a new winner, for the first time since Marin Cilic at the 2014 US Open, and for the first time since Stan Wawrinka at the 2016 US Open, it will be a non-Novak Djokovic, Rafael Nadal or Roger Federer.

© 2020 AFP