Serena Williams re-established her customary superiority, hammering Daria Gavrilova 6-1, 6-2 to reach the second round of the Cincinnati Masters on Monday.
Two-time Cincinnati champion Serena lost the Wimbledon final to Angelique Kerber last month.
Alexander Zverev will face 10th-seeded Greek 19-year-old Stefanos Tsitsipas in the ATP Washington Open semis.
Andy Murray, three-time Grand Slam champion, outlasted Romania's 93rd-ranked Marius Copil 6-7 (5/7), 6-3, 7-6 (7/4).
Andy Murray needed seven match points to subdue the 80th-ranked Mackenzie McDonald 3-6, 6-4, 7-5.
Murray, the 2013 and 2016 Wimbledon winner, had only just returned to action after 11 months on the sidelines due to a hip injury that needed surgery in January.
Andy Murray was due to play France's Benoit Paire in the first round on Tuesday.
Andy Murray is scheduled to play in his first round tie against France's Benoit Paire on Tuesday. But the former world number one, who was crowned Wimbledon champion in 2013 and 2016, is making slow progress in his return from hip surgery in January.
Roger Federer's 37th birthday may be fast approaching but the evergreen Swiss will be looking to clinch his ninth Wimbledon and 21st Grand Slam Title.
Seven-time Wimbledon champion Serena Williams has been seeded 25 for this year's women's singles by the organisers despite being ranked 183 in the world.
Murray, also the 2012 US Open winner, faces British rising star Kyle Edmund in the second round at Eastbourne on Wednesday.
Andy Murray gave an encouraging display in his first competitive match in 11 months after finally recovering from the hip problem that required surgery in January
With Wimbledon starting on July 2, Novak Djokovic is desperate to improve his lacklustre 14-8 record in 2018.
The former world number will return to action after hip surgery in January.
Andy Murray has not played a competitive match since his Wimbledon quarter-finals exit last July.
The three-time Grand Slam champion, who dislodged Novak Djokovic from the top of the rankings towards the end of 2016, has slipped to 19th in the world due to his lengthy lay-off.
Murray's withdrawal comes amid a string of injury concerns that have plagued some of the world's top players and cast doubt on their participation first Grand Slam of the year, which is due to begin in Melbourne on January 15.
Murray said on Sunday he felt in great shape and that he was confident he would play in Brisbane. But the 30-year-old Scot issued a statement Tuesday announcing his withdrawal from the tournament