Stanislas Wawrinka "happy" despite inconsistent performance in US Open first round

Stanislas Wawrinka has claimed that he is "happy" to progress from the first round of the US Open, but admits that his performance was inconsistent.

The two-time Grand Slam champion was tested, but came through a 7-5 6-4 7-6(6) victory over Albert Ramos-Vinolas.

"[I was] a little bit up and down," allsports.com quotes Wawrinka as saying. "In general it was a good match. It's always tough to play, never easy, especially first round.

"You need to get through those matches. I'm happy to get through in three sets. I think my level is there. Physically I feel good. I'm ready for the rest."

Wawrinka will take on Korea's Chung Hyeon in the second round.