Novak Djokovic has revealed that he believes he can win all four Grand Slam titles in a row once again, according to a report on the Tennis World USA.

The Serbian currently holds the Wimbledon and US Open titles and is confident that he can also secure the Australian Open and the French Open to achieve his goal.

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Djokovic held all four titles between July 2015 and June 2016 and believes that he still has what it takes to do it again.

The former world number one has been in great form in recent months after having a shaky start to the calendar year.

He said:

I have confidence. It’s some old-new self-confidence. Each season is a new site and a new challenge.

I am a different player and person than I was three years ago. I know that everyone wants to use the 2015 parameter as a benchmark for all the other seasons and to ask if it’s possible to repeat something like that… four in a row.

Do I believe that I can repeat that success? Of course I believe, otherwise, I would not play tennis.

I played Queens’ Finals, won Wimbledon, Cincinnati and the US Open and it’s a big run. I am grateful for this, because in the first few months after the operation, I had difficulty on the court. I had to make some adjustments, especially the service.

Djokovic is also targeting becoming the world number one again at the expense of long-term rival Rafael Nadal.