Djokovic admits 'private issues' derailed his pursuit of Grand Slam sweep

World number one Novak Djokovic has disclosed that his sudden slump in form was due to 'private issues' and not because of a lingering wrist injury.

The Serbian superstar, who saw his hopes of calendar-year Grand Slam end following a shocking defeat to American Sam Querrey in Wimbledon, however, confirmed that his personal problems had been resolved and that 'life is going on like everything else', news.com.au reported.

At Wimbledon, he was aiming to become the first man since Rod Laver in 1969 to win all four singles majors in the same season.

According to reports, Djokovic's off-court issues involved his wife, Jelena.

Drawn to face volatile Pole Jerzy Janowicz in the US Open first round, Djokovic's glittering season came to a sudden standstill with the Querrey loss and then first-round failure at the Rio Olympics.

The 12-time Grand Slam champion admitted that his wrist hadn't been in ideal shape for the last one month but insisted that he would do everything in his power to reach as close to 100 percent fitness during the course of the tournament at Flushing Meadows.

He also hoped that he would recover enough to execute his backhand shot with the same perfection as he used to be.