(CNN) -- World number two Roger Federer continued his perfect start to the U.S. Open, brushing aside Germany's Andreas Beck 6-3 6-4 6-3 on the Arthur Ashe Center Court.
The Swiss, who won the Flushing Meadows tournament five times in a row between 2004 and 2008, is yet to drop a set at the New York event.
Last year's beaten finalist took just one hour and 41 minutes to defeat Beck and will face France's unseeded Paul-Henri Mathieu in the third round, who carded a 7-6 6-4 6-3 victory over compatriot Guillaume Rufin.
Number three seed Novak Djokovic had to contend with crowd trouble on center court to overcome Philipp Petzschner, taking the match 7-5 6-3 7-6.
The incident occurred in the eighth game of the opening set, when there was a disturbance in the stands as Djokovic was set to claim the first service break of the match.
According to the New York Times, a fight broke our between a male fan and two spectators, a woman in her 40's and an elderly man.
The row culminated with both men falling over two rows of seats before the three individuals involved were handcuffed and taken to a local police station.
The 23-year-old Djokovic noticed the incident and told the newspaper: "It was far away from the court; we couldn't really see what was going on. I hope it was no Serbian up there."
Petzschner recovered to hold his serve, but Serbia's Djokovic got his break in the final game of the set to claim a straight-sets victory.
Russia's Nikolay Davydenko was stunned by Richard Gasquet, losing 6-3 6-4 6-2 to the Frenchman, who is ranked 38 in the world.
The fifth seed is the highest placed player to be eliminated so far in New York, and he was joined by fellow seed Marin Cilic, who also tasted defeat on day four.
Number 11 seed Cilic was undone by Kei Nishikori of Japan, eventually losing a five-set epic 5-7 7-6 3-6 7-6 6-1.
In a match lasting just under five hours, Croatia's Cilic took the opening set before Nishikori leveled the match courtesy of a second-set tie break.
It was a similar story for the next two sets, with Cilic claiming a comfortable win in the third, only for world number 147 Nishikori to pick up another tie break success in the fourth before crushing his higher-ranked opponent in the final set.
There were no such problems for Robin Soderling, who swept aside home crowd favorite Taylor Dent in a 6-2 6-2 6-4 win.
The fifth seed was a man in a hurry, defeating the unseeded American in one hour and 32 minutes.
There was reason to cheer for the home crowd, with New York native James Blake advancing to the third round at the expense of Canada's Peter Polansky.
The former world number four took the match in four sets, recovering from one set down to seal a 6-7 6-3 6-2 6-4 triumph.