Novak Djokovic of Serbia returns the ball with the between-the-legs shot against Carlos Berlocq of Argentina at the U.S. Open tennis tournament in New York. Picture - Reuters.

World number one Novak Djokovic displayed exactly why he has lost just two matches this year with a demolition of Argentina's Carlos Berlocq in the US Open.

He dropped just two games for a 6-0 6-0 6-2 win, progressing to the third round in the process, completing the match in 90 minutes.

Berlocq, the world number 74, couldn't manage the incredible pace of his Serbian opponent, and will be mighty relieved that he managed to take two games and save himself from the embarrassment of being the first man in 24 years to lose all three sets without a game.

The Argentine, 28, surprisingly broke Djokovic early in the third set and then went on to break the Serb again, although Djokovic broke back on both occasions. He took a point with a Federer-ish between-the-leg shot before sealing the win.

Djokovic later admitted the he could not play better as he displayed powerful tennis from the baseline with pin-point accuracy.

The first two sets were ideal, he said. I could not play better. I was getting a lot of balls back, I was ending the points when I needed to. I was making a lot of winners. My serve was okay, and my return was great.

I felt fantastic on the court. And there is not much I can say when everything seems fun and seems enjoyable when you're playing such good tennis.

We are professionals on the court, Djokovic went on. We need to do our job, obviously to win, regardless of who is across the net. I know Carlos off the court. He is a nice guy. Today on the court I had an answer for every shot. I played great.

I felt a little bit for him in a certain stage of the match in the third set where he was trying really hard to get back into the match. I have to give him credit for fighting.

Seven hours before Djokovic's master class, five-time champion Roger Federer  comfortably beat Dudi Sela 6-3 6-2 6-2.

The match lasted just 77 minutes on a windy afternoon at Flushing Meadows. But the world number three saw past 93rd ranked Israeli and will now face 27th seed Marin Cilic, who beat Australian youngster Bernard Tomic 6-1 6-0 6-2, in the third round.

I didn't have much trouble on my serve, and from the baseline I also had the upper hand, said Federer. When it's like that, obviously it's tough for the opponent.

I just think I was superior today.