World number one Novak Djokovic believes the key to winning the calendar slam will be overcoming the mental challenges rather than physical.
Djokovic will become the first man for more than 50 years to win all four majors in the same year should he win the US Open.
He easily defeated Tallon Griekspoor 6-2, 6-3, 6-2 to ease into the third round, and he says he knows what challenges await him.
Asked if the pursuit of the calendar slam was more taxing physically or mentally, Djokovic said: “Probably it’s more mental and emotional, really.
“Physically, I feel great. I can go a couple of hours every day. I don’t mind being on the court for a long time.
"Actually the longer the match goes, I feel I have more chances to win against anybody in best of five.
"So it’s really more about handling everything that is happening off the court, all the expectations.
"But as I’ve said, [it ’s] trying to take it moment by moment, really stay in the present moment, and get the most out of it.
"I’m as motivated as ever to do well. I’m not the only player who wants to go deep in the tournament.
"Hopefully, [I’ll] get my hands on the trophy. That’s why I’m here. I’m trying to be the best I can be every single day. Let’s see what happens.”
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