Three-time Grand Slam champion Andy Murray moved closer to a singles return six months after right hip surgery while Greece's Stefanos Tsitsipas rolled into the world's top five Friday at the ATP Washington Open.
Britain's Murray and his brother Jamie, in their first doubles event since the 2016 Rio Olympics, lost to New Zealand's Michael Venus and South African Raven Klaasen 6-7 (3/7), 7-6 (8/6), 10-7 in a quarter-final at the US Open tuneup event.
Murray has practiced singles this week to improve his conditioning after the long layoff.
"I feel fine," Murray said. "Practice has been fine. No issues physically. So progressing well. Just keep practicing the next 10 days or so and see what happens."
Top seed Tsitsipas beat French 10th seed Benoit Paire 7-5, 6-0 to reach the semi-finals and ensure he will overtake Germany's Alexander Zverev to crack the world rankings top five on Monday.
"Once you're in a certain position for a long time, you really crave for more," Tsitsipas said.
"This one position difference might not feel a lot for some people but for me it really means a lot because there has been a lot of hard work behind it, just a lot of suffering in general.
"I feel I deserve this position. It means a lot for sure."
The 20-year-old Australian Open semi-finalist, who lost to Zverev in last year's Washington semis, booked a semi-final against Australia's Nick Kyrgios, who ousted Slovakian lucky loser Norbert Gombos 6-3, 6-3.
"I'm excited to play him," Kyrgios said of Tsitsipas. "He's one of the best players in the world right now."
Murray, who feared his career might be over after the January operation, hasn't played singles since the Australian Open but says he might return at the ATP Cincinnati Masters starting August 12.
"If I feel like I'm ready, I'll give it a go. If not, I'll wait probably until after New York. But so far it has been fine."
Murray, set to play doubles next week at Montreal alongside Spaniard Feliciano Lopez, doesn't want his first singles matches back to be the best-of-five-set variety offered in Grand Slams.
He ruled out playing in Winston-Salem the week before New York, figuring he would be better off practicing for a post-US Open return.
"I've never competed the week before a Slam," Murray said. "If I'm not ready five or six days beforehand, I'm assuming that I'll probably just give it a miss."
The 32-year-old Scotsman, a former world number one now ranked 222nd, captured Grand Slam singles crowns at the 2012 US Open and at Wimbledon in 2013 and 2016.
- Tsitsipas's shoe issues -
The Tsitsipas victory was marked by his third straight game with a delay to change left shoes, having said he damages the laces when he slides incorrectly.
"There's nothing I can do about it," he said. "The only thing is probably change my footwork, stop doing that."
Russian third seed Daniil Medvedev advanced to the semi-finals by defeating Croatian sixth seed and 2014 US Open champion Marin Cilic 6-4, 7-6 (9/7).
Medvedev, chasing his fifth career ATP title, took the only break at the start and never faced a break point.
"I managed to do what I had to do, hold my serve and win the tie-breaker," Medvedev said. "I'm really happy with my level of play."
Next up for Medvedev will be 122nd-ranked German lucky loser Peter Gojowczyk, who outlasted British 13th seed Kyle Edmund 6-3, 4-6, 6-3.
Gojowczyk, who only made the event after Australian Bernard Tomic dropped out with a finger injury, won his only title in 2017 at Metz.
In the accompanying WTA event, Taiwan's 31st-ranked Hsieh Su-Wei lost to Catherine McNally 6-4, 6-3. The American faces Italy's Camila Giorgi in the semi-finals.
Russian qualifier Anna Kalinskaya ousted France's Kristina Mladenovic 6-4, 4-6, 6-2 to book a semi-final date with American Jessica Pegula.
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