Novak Djokovic will have to battle his nerves if he is to complete an incredible year and win the Calendar Slam, says Patrick Mouratoglou.
Djokovic has already won the Australian Open, Roland Garros, and Wimbledon in 2021, meaning he will complete the set if he can win the US Open too.
Such a feat has not been achieved for more than 50 years, and Djokovic has the added pressure of breaking the Grand Slam record should he win the tournament.
And, according to Serena Williams' coach Mouratoglou, that may be tough to deal with even for someone as mentally strong as Djokovic.
"This year is special for Novak, he was always far from the two others (Roger Federer and Rafa Nadal) in terms of number of Grand Slams," Mouratoglou told Eurosport.
"Now, he is equal – 20 – 20 – 20. So, he knows it’s an opportunity to really re-write history and I can feel that the tension throughout the year is getting bigger and bigger.
"The first two sets of the Roland-Garros final against Stefanos Tsitsipas I felt he was super nervous, much more than usual.
"At the Olympics, he kind of lost it a little bit, he got crazy angry and he lost. I can feel it building.
"This moment for him is a lot about dealing with his nerves.
"In the last tournament he played he lost in a semi-final against Alexander Zverev when he got crazy nervous so he has a bad taste in his mouth and he needs to get rid of it."
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