Monte Carlo - World No 1 Rafael Nadal said on Friday that he has spoken to Andy Murray about his injury woes, adding he knows how hard it is to not "see the light of how to improve".
Three-time Grand Slam champion Murray had hip surgery in Melbourne at the start of the year and is targeting a return for the grasscourt season, having not played since a Wimbledon quarter-final defeat by Sam Querrey last July.
"I saw him in Melbourne, and I spoke with him on the phone two weeks ago," Nadal said after his Monte Carlo Masters quarter-final thrashing of Dominic Thiem.
"He asked me about things. I don't want to tell you about the things that we talk because will not be fair for him, and I will not feel comfortable with it.
"But, yes, I tell him the things that I think worked for me."
Nadal has struggled in recent months with a hip injury himself, and is playing in his first ATP tournament this week since January's Australian Open.
"I have been in that situation," added Nadal. "I know how tough and frustrating (it) is when you work every day and you don't see the light of how to improve.
"You don't see any improvements. But then one day trying things, trying treatments, one day things are going better, no?
"That's what I really hope about him because he is important, very important, for our tour."
Murray had looked set for a period of dominance when he won the 2016 Paris Masters and became world No 1 for the first time, but hasn't won a title since March last year while seeing Nadal and Roger Federer power back into form.
The 30-year-old is expected to return at the grasscourt tournament at Rosmalen in the Netherlands the week after the French Open ends in June although he remains on the Roland Garros entry list.
But Nadal is confident that his old rival can return to the top of the game if he can get back to full fitness.
"If Andy is healthy, he will come back," said the 16-time Grand Slam champion.
"After a long period (of) time, maybe he will not be back and winning first week, but he will not forget how to play tennis.
"He knows that, and everybody knows that. If he is healthy, he will be back in a position to fight for the most important things."
Nadal cruised past Thiem for the loss of just two games on Friday and will play Grigor Dimitrov for a place in the Monte Carlo final as he bids for an 11th title in Monaco.