The three-time Grand Slam winner says he no longer has pain in his hip and it is now a matter of building up fitness so he can play several matches in a row at tournaments.
Andy Murray won two ATP Tour singles matches in a row for the first time in more than a year to battle into the China Open quarter-finals on Wednesday.
The former world number one outlasted fellow Briton Cameron Norrie 7-6 (8/6), 6-7 (4/7), 6-1 over nearly three gruelling hours and will play top seed Dominic Thiem or Chinese wildcard Zhang Zhizhen next.
The 32-year-old Murray, now ranked a lowly 503, is stepping up his comeback from a career-saving operation in January – and was at his vintage fighting best here.
He defeated US Open semi-finalist Matteo Berrettini on Tuesday in hot and hazy Beijing for his biggest scalp since his return to singles tennis in mid-August.
Murray showed several flashes of irritation as the first set against 69th-ranked Norrie went to the tie break, chuntering away in the direction of his coaching team courtside.
But he regained his composure and captured the set thanks to an untimely double fault by his compatriot.
The 24-year-old Norrie broke Murray's serve in the sixth game of the second set and Murray was struggling, bending over between points with his hands on his knees to catch his breath.
He shook his head as he slumped red-faced in his seat at 5-2 down and looked all in.
He displayed the battling qualities which took him to number one in 2016 to somehow surge back, only to lose the second set on the tie break.
But he somehow wrestled back the initiative in the decider, breaking Norrie's first service game on the way to a trademark gritty victory.