Stanislas Wawrinka had to come through a five-set epic to beat Steve Darcis in the second round of the US Open at Flushing Meadows.

Belgian Darcis took the opening set 8-6 in the tie-break, but the match was back on terms thanks to 18th seed Wawrinka's 6-3 triumph in the second.

With the third looking like it was heading for another tie-break, Darcis snatched a late break to clinch it 6-4.

Darcis then failed to convert a break point at the start of the fourth before he was broken three times as the Swiss levelled the contest 6-1 in emphatic style.

There was little to separate the two competitors in the deciding set, but Wawrinka again found a late break to close out the match 7-5 and set up a third-round encounter with Alexandr Dolgopolov.