Patrick Mouratoglou believes it is merely a 'matter of time' before Stefanos Tsitsipas becomes a Grand Slam champion.
Mouratoglou has been part of Tsitsipas' team for a while now, meaning he is better positioned than most to assess his current level.
Tsitsipas is currently at a career-high ranking of world number five, and has already won an ATP Tour Finals two years ago, and Mouratoglou has no doubt a Grand Slam success is in his future too.
"I think Stefanos’ level of tennis is very high," Mouratoglou told sport24.gr. "When he plays at this high level he can beat anyone."
"He has already beaten the best: Roger Federer at a Grand Slam, Novak Djokovic and Rafa Nadal at a Masters 1000.
"His low level was very low in the past and that is why he often lost early in Grand Slams. What happened at the most recent US Open against Borna Coric.
"You have good days and bad days during a Grand Slam that lasts 15 days. Whoever wins a Grand Slam is capable of winning a match even on a bad day.
"I think the answer to the question of whether he can win a Grand Slam is yes. It’s a matter of time.
"It is difficult to say when but he is on the right track."
Tsitsipas has shown some steady improvement, and came back from two sets down to beat Rafael Nadal at the Australian Open.
That improvement, according to Mouratoglou, is largely down to the Greek ace maturing both mentally and tactically.
"He used to panic often in these moments that are psychological but also [those that are] a matter of tactics.
"Because he was in a panic, he was playing very fast and very flat and you add stress to the already existing stress.
"When you play flat, the ball returns flat and you can not speed up the game in moments of pressure and stress. This takes stress to the next level.
"I think he has understood that and now he plays with more height and depth in the moments when he is under pressure."
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