US Open 2017: Rafael Nadal beats a dogged Leonardo Mayer to reach last 16

The world number one has struggled to find anything like his best form in New York so far and, after his struggle against Taro Daniel in round two, it was a similar story against lucky loser Leonardo Mayer.

The Argentinian took the opening set on a tie-break and it was not until Nadal finally converted his 14th break point to lead 4-3 in the second that the Spaniard turned on the style.

Nadal won 16 of the final 21 games to clinch a 6-7 (3/7) 6-3 6-1 6-4 victory and a place in the last 16, where he will take on Alexandr Dolgopolov.

The Spaniard has been out of sorts on the North American hard courts, losing to Denis Shapovalov and Nick Kyrgios in the build-up to Flushing Meadows.

Return of serve has been a particular problem for the Spaniard and he was made to pay for not taking his chances in the opening set against Mayer.

The world number 59 had never won a set in three previous matches against Nadal but grew in confidence and ruffled his opponent with the quality of his single-handed backhand.

Nadal played a poor tie-break and things might have turned out very differently had he not saved two break points in the fourth game of the second set.

Mayer seemed to sense an opportunity lost and began to make a lot more errors, although it took Nadal a while to capitalise.

After missing three break points in the following game, failing to make a return on any of them, the top seed finally took his fifth chance at 3-3, pumping his fist in celebration.

A running forehand winner gave Nadal the set, and Mayer was 3-0 down in the third before he won another game.

With the night-session crowd waiting outside in the rain for Roger Federer’s clash with Feliciano Lopez, Nadal did his best to finish the match quickly.

But Mayer managed one final act of defiance, breaking the Nadal serve at 5-2 in the fourth set before the Spaniard took his second chance after three hours and 16 minutes.