Defending champion Roger Federer was given a tough passage into the third round of the US Open before overcoming Fabrice Santoro 7-5 7-5 7-6.
The Frenchman produced a dazzling array of shots to regularly rattle the world number one and cancel out a 5-1 deficit in the opening set.
But Federer broke again in the 12th game to round off the set.
He won the second set by the same scoreline before a sublime tie-break in the third, which he won 7-2.
"I always enjoy playing against him," said Federer. "He gave me a lesson that first time I played him (in 1999).
"He sizzled me with his slices. It's so different playing against him. We had a great match."
He was joined in the third round by Lleyton Hewitt, who also had to see off an unexpectedly tough challenge from Jose Acasuso.
Hewitt came through 7-6 (8-6) 7-6 (7-3) 6-2 against the big-hitting Argentine.
Acasuso lost focus following a disputed line call just before the second-set tie-break and never recovered.
Hewitt is likely to be tested yet further in the third round where he faces big-serving Taylor Dent, who beat Nicolas Almagro 6-3 6-2 4-6 7-5.
Asked about Hewitt's behaviour on court, Dent said some of it could not be considered "super sportsmanship".
Hewitt responded: "It doesn't faze me a whole heap.
"It's still a matter of me going out there Sunday and playing my game and not worrying about who's at the other end too much. It's water off a duck's back."
And Dent added: "If I was his coach, I'd say keep doing it. At the end of the day, I'm not going to lose the match because he's cheering on my bad shots."
Paradorn Srichaphan showed flashes of his form of old as he upset sixth seed Nikolay Davydenko 6-4 7-5 6-3.
The 26-year-old Thai, a former world number nine, has seen his ranking slide to 51st but was in fine form on Friday.
Srichaphan ripped 45 winners against his Russian opponent, who reached the semi-finals at the French Open and the last eight at the Australian Open.
The Thai will next face David Sanguinetti, who beat Carlos Moya.