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 picked up a vital break of serve to take a 4-2 lead and looked well set to progress to the quarter-finals until the Romanian valiantly fought back and ensured the match would be decided with a tie-break.But Murray eventually came through and shared a touching moment at the net with his beaten opponent before he couldn't contain his emotion any longer.

That speaks volumes on just what being back on court truly means to the Scot.

After the epic three-setter Copil classily tweeted a message of congratulations to Murray and revealed he told him 'what he deserved to hear' when they shook hands.

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.