Novak Djokovic and Roger Federer each recorded straight-set victories to ease into the second round of the U.S. Open, while American teen Victoria Duval pulled off the biggest upset of the tournament so far by stunning a former champion.

Djokovic underwent an early test Tuesday evening against promising Lithuanian Ricardas Berankis, but he passed it with flying colors in a 6-1, 6-2, 6-2 rout.

The Serbian world No. 1, winner of the 2011 U.S. Open, was well aware of the ball-striking talent of his 23-year-old opponent and came out focused and determined not to give him any hope.

"I played every point like it's a match point," Djokovic, who needed just an hour and 22 minutes to clinch the victory, said afterward.

Next up for the Serb will be Germany's Benjamin Becker.

The 32-year-old Federer, a five-time champion of this Grand Slam event, employed a big-hitting style in a comfortable 6-3, 6-2, 7-5 victory Tuesday afternoon over Slovenia's Grega Zemlja.

The Swiss great, whose ranking has fallen to No. 7 after a disappointing summer, said he saw early on that his opponent was throwing caution to the wind and decided not to let him dictate the points.

"I decided also to play aggressive. By doing that, didn't have many rallies. It was more of a serving contest," Federer, who will next take on Argentina's Carlos Berlocq, said in the post-match interview.

In a big upset Tuesday, Duval, a 17-year-old Haitian-American ranked No. 296, rallied to upset Australia's Samantha Stosur, the 2011 champion, 5-7, 6-4, 6-4. EFE