Four-time defending champion Roger Federer seeks a 30th consecutive US Open victory Sunday against Czech Radek Stepanek with Serbian third seed Novak Djokovic also looking for a spot in the last 16.
Swiss superstar Federer, remains two Grand Slam titles shy of Pete Sampras' all-time record of 14 as he tries to become the first player since Bill Tilden in 1924 to win five US titles in a row.
Federer's win streak at Flushing Meadows since losing to David Nalbandian in the round of 16 in 2003 does not include a fourth-round walkover in 2004. He has not fallen short of the fourth round at a Slam since the 2004 French Open.
Second seed Federer was bumped from the world number one ranking by Spain's Rafael Nadal two weeks ago after Nadal defeated Federer in the French Open and Wimbledon finals earlier this year. Never in history have players met in the finals of three consecutive Slams in the same year.
Djokovic, who lost to Federer in last year's US Open final, will face Croatia's Marin Cilic in a night match at Arthur Ashe Stadium.
Russia's Nikolay Davydenko, the fifth seed, faces compatriot Dmitry Tursunov and American eighth seed Andy Roddick meets Italy's Andreas Steppi in other matches involving top men's seeds Sunday at the year's final Grand Slam event.