Andy Murray in tears after gruelling victory over Marius Copil

An emotional Andy Murray continued to make encouraging strides on his comeback from hip surgery as he booked his place in the quarter-finals of the Citi Open in Washington.

The 31-year-old Scot, who withdrew from Wimbledon after deciding he was not quite ready to compete, showed impressive reserves of fitness to see off Romania’s Marius Copil 6-7 (5/7) 6-3 7-6 (7/4).

The match in the US capital lasted three hours and two minutes and finished just after 0300 local time, and Murray buried his head in his towel at the conclusion of the match, apparently sobbing.

He will next face Australia’s Alex de Minaur in the last eight on Friday evening.

Copil proved a testing opponent, breaking back when Murray appeared set to move clear in the decider.

Murray, who underwent hip surgery in January, reached this stage with wins over Mackenzie McDonald and fellow Briton Kyle Edmund, and now faces world number 72 De Minaur for a place in the semi-finals.

Cameron Norrie also had a good night, as his 6-4 6-4 win over Adrian Mannarino of France took him into the semi-finals of the Abierto Mexicano in Los Cabos. He will face Italy’s Fabio Fognini for a place in the final.

Norrie won nearly three-quarters of his first serve points as he dismissed the
fourth seed and world number 25.

Heather Watson took Venus Williams to three sets before succumbing 6-4 4-6 6-0 at the Mubadala Silicon Valley Classic in San Jose.

“(I just wanted to) control the points and enjoy the battle, just get out there and try to do what I know that I can. It worked out, thankfully.”

Katie Boulter crashed out of the Citi Open women’s singles after losing in three sets to qualifier Allie Kiick in the second round.