Andy Murray's wild card run at the ATP Cincinnati Masters ended on Wednesday with a 7-6 (7/4), 6-3 loss to Poland's Hubert Hurkacz.

The Scotsman, who has been struggling to re-establish himself on tour after his latest injury -- a groin problem -- lost the second-round contest in one and three-quarter hours to the player who knocked Roger Federer out of Wimbledon.

Murray fired a respectable 11 aces to the 17 of his ninth-seeded opponent in the first-time meeting while saving four break points.

"This week was fairly positive. I played much better than at Wimbledon and the grass season," he said.

"This week my body felt good, even if hardcourts are not easy on the body.

"Physically I was tired after some of the long rallies, but I felt fine."

The 34-year-old said the only factors that would make him reconsider his comeback were "if my body doesn't feel good " or "my tennis starts going backwards."

The two-time Cincinnati winner, ranked 105th, owns 14 career Masters 1000 titles, the most of any man in a field missing the "Big 3" trio of Federer, Rafael Nadal and Novak Djokovic -- all 20-time Grand Slam champions.

Olympic silver medalist Karen Khachanov joined Murrray in defeat as the Russian exited 6-7 (5/7), 6-3, 6-4 to Canada's 12th-seeded Felix Auger-Aliassime.

The winner will next face Wimbledon finalist Matteo Berrettini for a quarter-final place.

Former champion Grigor Dimitrov reached the third round over Kazakh Alexander Bublik 6-3, 7-5.