World No 1 Novak Djokovic resisted a stiff first-set challenge before defeating Benjamin Becker 7-6 (2) 6-2 6-2 to reach the third round of the US Open.
The Serb faced two set points against the German, but Becker failed to take advantage and Djokovic prevailed in an hour and 51 minutes.
Once Djokovic had weathered the early first set storm it was plain sailing for the 2011 champion who lost just four games the rest of the way.
The top seed, who is bidding to make the final for a fourth successive year, sent down 13 aces as well as 40 winners with 18 of his 26 total unforced errors coming in that uncomfortable first set.
"Becker is a quality player and he should have won the first set. I was fortunate to come out of it, but after that I felt more comfortable on the court," said Djokovic.
"There were tough conditions and I wasn't playing as well as I could.
"We have been working hard the last 10 days and my team has been helping me to get to the highest level possible."
The 87th-ranked Becker is already part of US Open folklore, having inflicted the last professional defeat of Andre Agassi at the tournament in 2006.
Djokovic goes on to face Joao Sousa for a place in the last 16 after the man from Portugal knocked out Finn Jarkko Nieminen 1-6 6-3 3-6 6-3 6-4.
Meanwhile, Tomas Berdych - the fifth seed - battled his way to a 7-6 (7/3) 7-6 (7/3) 6-3 triumph over American Denis Kudla, while 12th seed Tommy Haas saw off Lu Yen-Hsun of Taiwan 6-3 6-4 7-6 (7/3).
Fellow seeds Andreas Seppi and Mikhail Youzhny also progressed thanks to respective straight set wins over Somdev Devvarman and Alexandr Dolgopolov.
In an all-French battle for a place in round three, 31st seed Julien Benneteau defeated Jeremy Chardy 6-4 6-3 6-4.
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