Rafael Nadal, the defending champion, reached the last 16 of the US Open last night with a 7-6, 6-1, 7-5 victory over close friend David Nalbandian.
But it was an uneven performance from the second-seeded Spaniard, who endured a first set hiccup when he trailed the 76th-ranked Argentine 3-5, and was broken when he served for the match in the ninth game of the third.
Up next for the 10-time grand slam title winner is Gilles Muller, of Luxembourg, who eased past Russia's Igor Kunitsyn 6-1, 6-4, 6-4, for a place in the quarter-finals.
"It was a tough day. David is a fantastic player and a close friend who has had a tough time with injuries," said Nadal. "The first set was key when I came back when he was serving for the set. I am happy because I played my best match of the tournament so far."
Nalbandian, who reached No 3 in the world in 2006 before his career was stalled by hip and groin surgery, went into the tie with a 2-2 career record against Nadal.
And he was far from unbowed in the opening set when a game plan of all-out attack, which witnessed 18 winners and 23 unforced errors, almost paid dividends before the Spaniard played a more composed tie break.
That gruelling effort took an immediate toll on Nalbandian, who was broken three times in the second set. He stopped the rot with a surprise break in the opening game of the third, Nadal's concentration not helped by being hit with a time code violation for taking too long between points.
The Spaniard, bristling at the decision, took out his frustrations by breaking back before immediately calling a medical timeout for treatment on his blistered right foot.
Nadal was another break to the good on his way to a 5-2 lead before the dogged Nalbandian clawed back to 5-5, boosted by a break when the world No 2 served for the match at 5-3.
But the second seed held for 6-5 and claimed victory in the 12th game when Nalbandian, whose final error total climbed to 60, served up a seventh double fault.