Andy Murray said he'd "never had that loss of strength before" after lasting only five games before retiring injured from Queen's on Wednesday -- casting a shadow over a possible farewell appearance for the British tennis great at Wimbledon.
Murray was in evident pain right from his very first serve against Australia's Jordan Thompson and eventually withdrew from the second-round match at 4-1 down with a leg problem caused by a related back injury.
"I never had that loss of coordination, control and strength in my leg before," Murray told reporters, with the five-times Queen's winner and twice a Wimbledon champion explaining neural pain in the right side of his back had led him to lose all the power in his right leg.
"I've been struggling with my back for a while -- I had lost the power in my right leg so lost all motor control, I had no coordination and couldn't really move.
"I was happy with the win yesterday but my back has been a problem for quite a while and it's been sore in the build-up to the tournament and was sore in my match yesterday and through to today," said Murray, adding that he's "dealt with back issues for about 10 years or so".
'Not a usual feeling'
The 37-year-old Scot, who confirmed he would have a scan on Thursday, added: "I was able to manage it -- it wasn't comfortable but during my pre-match warm-up I was pretty uncomfortable and when I walked up the stairs just before the match I didn't have the usual strength in my leg, it wasn't a usual feeling."
Murray, who competes with a metal hip and has struggled with an ankle injury and a back issue this year, had a medical time-out when 1-2 down at the changeover.
But he was unable to chase down anything out of reach and rolled in gentle first serves. Murray, who has plummeted to 129th in the world rankings, eventually withdrew at 4-1 behind.
He waved to a crowd including both his wife and mother, with spectators applauding Murray off the court.
The former world number one has spoken of wanting to retire either after Wimbledon or the Paris Olympics, with Murray a two-time gold medallist.
But Wednesday's injury could scupper the three-time Grand Slam winner's plans, with Wimbledon starting in under a fortnight.
"I could see he had a problem in the warm-up and then his first serve," said Thompson.
"I learned a lot of things watching him play, so it's an honour to share the court with him, but it's just sad that it ended like that."
Meanwhile, Sebastian Korda maintained his impressive start to the grass-court season as he defeated 2014 Queen's champion Grigor Dimitrov, the third seed, with a hard-fought win.
The 23-year-old American advanced into the last eight with a 6-4, 3-6, 7-5 victory over his Bulgarian opponent, with Korda having also gone all the way to last week's final at 's-Hertogenbosch -- also a Wimbledon warm-up -- before losing to Australia's Alex De Minaur.
Korda will next play Rinky Hijikata after the Australian qualifier defeated Italian Matteo Arnaldi 7-6 (7/0), 7-6 (9/7) to reach his third tour-level quarter-final of the season.
Carlos Alcaraz, the defending Queen's champion who won his third Grand Slam at the French Open earlier this month, is due on court Thursday to face Britain's Jack Draper.