CINCINNATI, Aug 20 — Daniil Medvedev and Stefanos Tsitsipas advanced to a semi-final showdown after both dismissed American opponents at the ATP and WTA Cincinnati Masters on Friday.

Top seed Medvedev fired 18 aces among 30 winners in a 7-6 (7/1), 6-3 defeat of Taylor Fritz in their Friday quarter-final.

Tsitsipas, semi-finalist at the last two editions, weathered a brief first-set rain interruption on the way to his 7-6 (7/5), 5-7, 6-3, defeat of John Isner, playing here for the 15th time at age 37 and the oldest quarter-finalist since 1969.

The Greek fourth seed won the opening set in a tiebreaker but found himself level at a set each after Isner slammed down an overhead to break in the penultimate game and served to square the match a game later.

In the third, Tsitsipas secured a break for 4-3 as Isner went wide; the seed sent over a service winner on his first match point to advance after more than two and a quarter hours despite 18 Isner aces.

"It’s never easy to play him, due to all his variations of play,” Tsitsipas said. "The most important thing is to stay patient.

"The match came down to a few points. I was able to hang in there and make one more ball — he didn’t give me a lot to work with.”

Tsitsipas added: "Against Medvedev, I need to be concentrated and approach my game in a precise manner.

"I will let my tennis do the talking.”

Medvedev, the 2019 tournament winner, strengthened his grip on the world number one ranking at the last major tune-up prior to the US Open, earning his victory over 11th seed Fritz in one hour, 40 minutes.

"The second set was much better than the first,” Medvedev said. "Taylor is a great player, from the baseline he didn’t give you much space.

"He was hitting the ball strong, making a lot of good points.

"But I’m happy with my level. If I can continue play this way and raise my level during matches I can beat anybody,” added Medvedev, who leads semi-final opponent Tsitsipas 7-2 in head-to-head meetings.

Keys downs Rybakina

In the women’s quarter-finals, Wimbledon champion Elena Rybakina saved three match points before falling 6-2, 6-4 to Madison Keys.

The Kazakh, who lifted the All England Club trophy last month against the odds, exited the pre-US Open event in 92 minutes as she went down to the American titleholder from 2019.

The pair struggled through a 21-point, 12-minute opening game, with Keys then turning on her jets to win the second in just over a minute.

Keys also came from a break down in the second set to carve out victory.

Rybakina, who stands 4-3 since Wimbledon, was broken five times and managed only 11 winners. Keys struck 21 winners and 16 unforced errors.

"Elena is a remarkable player who can turn a match around at any moment,” unseeded Keys said. "I needed to stay out front.

"It felt like I needed 12 match points, so I’m very happy to get the win, added Keys who on Thursday ousted world number one Iga Swiatek.

Keys next plays Petra Kvitova, a two-time Wimbledon champion who defeated Australian qualifier Ajla Tomljanovic 6-2, 6-3.

"I have obviously had some battles against Petra. Won some, lost some,” Keys said of the Czech, with whom she has split eight matches.

"It’s never easy to play her, especially later in a draw, meaning that she’s playing some very good tennis.”

Kvitova remains wary of an opponent she defeated here in the first round a year ago.

"She’s really on fire. I love how Madison is playing. She’s playing like one of the best. She’s playing beautifully. It’s nice to see.

Second seed Aryna Sabalenka ended the dream run of Zhang Shuai with a 6-4, 7-6 (7/1), defeat after the Chinese player had put out Naomi Osaka and second seed Anett Kontaveit. — AFP