NEW YORK - Fourth seed Alexander Zverev out-duelled fellow German Maximilian Marterer 6-2 6-7(5) 6-3 6-2 in the first round of the US Open on Monday.

Zverev, seeking a debut Grand Slam title after reaching the Australian Open semis and the Roland Garros final this year, flexed his dominant serve as he blasted 21 aces on the Grandstand.

Unseeded Marterer, the "lucky loser" that entered the draw after Emil Ruusuvuori withdrew last week, captured a close second set but was ultimately overpowered by the world No 4.

Zverev looked sharp in the first set, breaking his opponent's serve in the opening game before Marterer battled back to claim a back-and-forth second set in a tiebreak.

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The big-serving Zverev looked frustrated at times, tossing his racket at the start of the third set after committing one of 44 unforced errors.

Zverev called his topsy-turvy performance in the year's final major a typical opening round for him, and said he expects to shore up his game in upcoming matches.

"I'm not usually the type of player that plays extremely well in first-round matches," Zverev said, citing an undesirable 11am start.

"I feel like I had a very good practice week so far here. I know that I have good tennis in me, and it's about showing that on the match court.

"I think my performance will improve over the next few matches."

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The win sets up a second round clash with either Frenchman Alexandre Muller or Australia's Adam Walton.