Andy Murray's former coach Alex Corretja said on Saturday that he was indestructible at the height of his career after the Briton announced he would retire this year due to hip problems.
Three-time grand slam champion Murray held a tearful news conference on Friday saying he planned to bow out at Wimbledon in July if his hip allowed him to play on.
The 31-year-old has drawn Corretja's fellow Spaniard Roberto Bautista Agut, who is the 22nd seed, in the opening round at the Australian Open which starts on Monday.
"He is someone who simply never gets fatigued. Indestructible," Corretja, who worked on and off with Murray from 2008-11, told Eurosport.
"Andy is someone who will fight for everything. He is someone who was always searching for something huge.
"Ever since I have known him he always wanted to be number one and win slams. He wanted to do something big for the Davis Cup and did it. He was always someone who challenged himself."
Murray twice won Wimbledon (2013 and 2016) following his first major title at the US Open in 2012 and helped Britain win the Davis Cup in 2015.
He has also lost five Australian Open finals and a French Open decider.
Corretja described Murray's style as something of a throwback, saying he may have lacked the explosive power of some of the modern generation but knew how to outwit opponents, agreeing with former US Open champion Andy Roddick that he was unrivalled as a tactician.
"He showed that even if tennis has changed a lot and evolved - people saying you need to hit every ball so hard, you only play for three or four shots and that's it - he showed that there is more to tennis than that," former world No.2 Corretja said.
"If you are smart, if you are consistent and you know where to place the ball every time then you can be number one and you can win slams on any surface. He found a nice balance between being defensive and aggressive.
"It was a privilege to see the way he reads a match. I think the way he could adjust to his opponents was one of his greatest assets and strengths."
When Murray does hang up his racquet for good, Corretja said the Scot would have a great career behind a microphone if he chose to go down that path.
"I would love Andy to be a commentator with me," he said. "He would be an amazing commentator. He has got an unbelievable sense of humour."