Andy Murray says it would be "a bit naive and silly" to think he can recapture the form that took him to world number one and three grand slam titles.
The 32-year-old Scot is fighting his way back after undergoing career-saving hip surgery, and he plays four tournaments in the next four weeks as he steps up his comeback.
Murray looked finished, or as good as, at the start of the year when he said Wimbledon would be his final event before retiring.
He had a change of heart after a successful operation and is determined to make a fist of a new lease of life, after saying he is now pain-free for the first time in years.
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But results have been shaky in his tentative return to singles action, with Murray losing a pair of first-round matches in Cincinnati and Winston-Salem before stepping back to play on the lower-tier ATP Challenger Tour and finally rediscovering a winning touch.
He won a pair of matches at the low-profile Rafa Nadal Open in Mallorca, but Murray wants to compete at the top level, even if he is not winning tournaments consistently.
"I'm not expecting to get back to my very best," he said, according to BBC Sport. "I think it would be probably a bit naive and silly to think that would be the case.
"I do feel like tennis-wise I can still compete at the highest level in terms of my skill, it's just whether physically I can get to a high enough level to be competitive right at the top."
Andy Murray practice at Hengqin Tennis Center.
— Zhuhai Championships (@ZhuhaiChampions) September 21, 2019
What do you expect to see from him at #ZC19 ?@ATP_Tour @andy_murray pic.twitter.com/xHXaxKJkCi
Murray will have a better idea of his future prospects in a month's time, and he begins his busy schedule by playing the Zhuhai Championships in China, facing American Tennys Sandgren in the first round.
World number 69 Sandgren beat Murray in Winston-Salem, so it will be a chance to avenge that loss and show whether the former Wimbledon and US Open champion - a long-time member of the 'big four' in men's tennis - is making progress.
Murray said, on the ATP website: "I don't know how far I'm going to be able to get now on my comeback. I don't know how much improving I still have to do or if I'm going to be able to. But I'm in no pain just now, so I might as well give it a shot and see how far I will go with the recovery."
He plays events in Beijing, Shanghai and Antwerp after the Zhuhai tournament, and Murray is targeting a run of match wins to show he can become a force again.
"I'd like to try to get 12 to 15 matches between now and the end of the year so my body gets used to competing and playing matches consistently again," he said.
"I hadn't done that for two years. It's been a really long time, so it takes time for your body to build up."