Boris Becker has not ruled out a coaching reunion with Novak Djokovic but says the Serb must first rediscover his love of the game.
Becker also explained how Djokovic lost motivation after winning last year's French Open, which was his first triumph at Roland Garros and meant he held all four grand slam titles.
Since then, the 29-year-old has endured early exits at Wimbledon and the Olympics before crashing out in the Australian Open second round to wildcard Denis Istomin last week.
He also surrendered the world number one ranking to Andy Murray in November.
Djokovic split with Becker at the end of last season and has said he is not looking to replace the six-time major champion.
Becker, however, who is commentating on the Australian Open for Eurosport, did not close off the possibility of a return.
"I have high hopes for Novak. He just has to re-focus," Becker said.
"Would I go back and coach him? I'll always be a friend and I'll always be in his corner. We are on very good terms. I don't know, let's see what happens.
"I learnt a lot from my time coaching Novak. I used to think I know how tennis was played today. I didn't know before I worked with Novak.
"I think it's a whole different experience and I'm very grateful for it. Let's see what the future brings."
Djokovic's shock defeat in Melbourne means he is now unlikely to claim back the world number one spot until after Wimbledon at the earliest.
Becker admits his former charge's success at the French Open seven months ago altered his perspective.
"You have to prioritise tennis again and I hope he does," Becker said.
"People don't realise what it takes to win one grand slam. Imagine he won four in a row, he was the holder of the real grand slam.
"A lifelong dream was fulfilled. Of course the bubble burst. Of course your mind goes off course. Of course his family wants him back. He's a human being with a big heart.
"He's a strong player and of course the motivation goes a little bit. To get it back you have to go back to the practice court and it's not easy when you've been on top here."
With Djokovic gone, Murray looked primed to go all the way at the first grand slam of the year, where he has reached the final five times but never won.
The Scot, however, bowed out to world number 50 Mischa Zverev and Becker suggested the pressure of sitting top of the rankings may have played a part.
"I think Andy Murray learned a lot from Novak and he was the better professional in the second half of last year," Becker said.
"But then he is number one and you saw what happened here in Melbourne - it's a whole new ball game. It's another world and the pressure is different.
"Going back to Novak and credit to him for being number one for such a long time - it's a different world up there."
Source: PA
