Melbourne - Doubles legend Bob Bryan is backing "madman" Andy Murray to play for "many more years" despite the Briton being forced out of the Australian Open with another injury.
The veteran American had a major hip operation in 2018 but bounced back to continue his hugely successful doubles partnership with twin Mike.
Three-time Grand Slam champion Murray had similar, career-saving surgery 12 months ago and in October won his first title since going under the knife.
But the 32-year-old pulled out of the Australian Open with a pelvic injury and last week further delayed his comeback, renewing fears for his tennis future.
"I talked to him last week," the 41-year-old Bryan said on Sunday in Melbourne.
"He's got something unrelated to the hip injury -- his hip feels great.
"All his numbers are off the charts, he tests the speed and the strength.
"He's right back where he was when he was number one, which is incredible. That's good to hear."
Murray has taken inspiration from Bryan as the Briton attempts to recapture a semblance of the form and fitness that made him world number one in 2016.
Bryan said that he has no issues with his hip -- Murray has consistently said that he is also now pain-free, but the pelvic problem is a fresh setback.
The American cited a recent documentary about Murray which charted the Briton's painstaking comeback.
"If anyone saw the documentary, you'll know how crazy he is with the work, he's a madman," Bryan said. "He's going to put it in, he's going to do everything he can.
"I expect to see him playing for many more years, winning."