CINCINNATI, Aug 16, 2025 (BSS/AFP) - World number two Carlos Alcaraz fought off a fierce challenge from Andrey Rublev to reach the semi-finals of the ATP-WTA Cincinnati Open on Friday as women's defending champion Aryna Sabalenka was sent crashing by Elena Rybakina.

Spain's Alcaraz broke Rublev in the final game of a tense duel to emerge a 6-3, 4-6, 7-5 winner and will face third-seeded Alexander Zverev, who brought the winning run of fifth-seeded Toronto champion American Ben Shelton to its end with a 6-2, 6-2 victory.

Germany's Zverev complained of feeling dizzy and out of breath as he led by a set and a break, but benefitted from 27 unforced errors from a listless Shelton over 76 minutes.

Zverev earned a 4-1 lead in the second set as Sheldon angrily tossed his racquet on the changeover, and the 2021 champion polished off the win on a second match point and now has 24 hours to try and get fit.

"I'm not feeling too great now, but I have a day to get fresh," Zverev said. "I hope to be at 100%.

"I'm not sure what happened. I felt very well but at the end of the first set it got progressively worse.

"But I'll do all I can to give it a shot tomorrow."

Alcaraz was broken while serving for victory at 5-4 in the final set against 11th-ranked Rublev, but he found his focus and used his trademark grit to come through three games later.

He sealed the triumph as an emotional Rublev hit an eighth double-fault on match point.

"I maintained the positive thoughts even if I lost focus a bit in the second set," said Alcaraz, whose five titles so far this year include the French Open as well as Masters 1000 trophies in Monte Carlo and Rome.

"Against Andrey, if you lose focus it can cost you the set -- or the match ... (Fighting back) is what I'm most proud of."

- Rybakina revenge -

Top seeded Sabalenka had no answer for 2022 Wimbledon champion Rybakina, who beat the Belarusian 6-1, 6-4 to book a semi-final meeting with Wimbledon champion Iga Swiatek -- a 6-3, 6-4 winner over Anna Kalinskaya.

Rybakina claimed a fifth victory in her 12-match personal rivalry with Sabalenka, avenging a loss to the Belarusian in Berlin two months ago.

Rybakina was aided by 11 aces as she reached her first Cincinnati semi-final.

"I'm happy with the serve. It was the key today," Rybakina said. "I served really well.

"If she had been serving well it would have been a totally different match," she acknowledged.

Rybakina has won her last three matches against Swiatek, all played this season.

Swiatek needed 93 minutes and five match points to get past Kalinskaya in what she called "the best match I played here.

"I'm happy that I'm progressing during the tournament," said the former world number one from Poland.

I just played my game," she said. "It was not easy but I'm happy that I stayed solid and kept my intensity,"

In other quarter-final action, Veronika Kudermetova crushed Varvara Gracheva 6-1, 6-2 and awaits the winner of Friday night's match between world number two Coco Gauff and ninth-ranked Jasmine Paolini.