NEW YORK, Sep 3 (Reuters) Third seed Novak Djokovic of Serbia stormed into the fourth round of the US Open by sweeping past Juan Martin Del Potro of Argentina 6-1 6-3 6-4.

Djokovic fired a forehand that handcuffed Del Potro at the net to end the one hour, 42-minute match yesterday and advance to the round-of-16 against another Argentine, 23rd seed Juan Monaco.

Monaco beat compatriot Agustin Calleri 7-6 6-2 6-4 in his third-round match.

The easy victory in Djokovic's first match on Arthur Ashe Stadium court was in sharp contrast to his five-set marathon victory over Czech Radek Stepanek in the second round.

Djokovic landed 74 percent of his first serves including seven aces and was broken only once by 18-year-old Del Potro.

''I'm happy the way it went after the second-round match was almost five hours,'' the 20-year-old Serbian, a semi-finalist at the French Open and Wimbledon, told the crowd.

''This is the first time in my life I experienced the biggest court in tennis. It's an amazing experience.

''I'm happy the way I played. Hopefully I will play even better in my next match.'' Reuters TB GC0942