Rafael Nadal has fought his way to a straight-sets victory over Diego Schwartzman in the US Open second round.

The two-time champion didn't have it all his own way against the world number 74 but he did enough to secure a 7-6(5) 6-3 7-5 win.

Nadal showed in his first-round win over Croatian prospect Borna Coric that he had arrived at Flushing Meadows with the aim of playing freely and without expectation, and he began his tussle with Schwartzman on the front foot, breaking the South American in the second game.

At 5-2, it appeared as though the Spaniard would wrap up the opener with minimal fuss, but Schwartzman surprised the left-hander by breaking back to take the set into a tie-break.

However, after the opening eight points were shared, Nadal's heavy-hitting wore down his opponent and he was able to edge into the lead after a set that had lasted 58 minutes.

Schwartzman stole an early march on Nadal at the start of the second, but he couldn't maintain his lead and the former world number one was able to take six out of the next seven games to move into a two-set advantage.

The third saw Schwartzman continue to trouble Nadal, who once again made a slow start to a set, but like in the second, he got back on level terms before in the 12th game he raced to three match points on Schwartzman's serve, taking the second to set up a last-32 match with Fabio Fognini.