Jo-Wilfried Tsonga finished his first-round US Open match strongly as he beat Juan Monaco in four sets this evening.

The ninth seed made a steady start as he picked up an early break in the first set against the Argentine, which was enough for him to take the opener.

Monaco cut out the errors in the second to level the match, but the Frenchman got the better of him in a third-set tie-break to regain the lead.

Tsonga appeared to gain confidence from winning the third set, making a strong start to the fourth as he raced to a 5-0 lead.

The ninth seed tried to wrap the match up on Monaco's serve, but his opponent did just enough to get on the board in the fourth set before Tsonga served it out next time around to progress.

Tsonga will face the winner of the match between Ireland's James McGee and Aleksandr Nedovyesov of Kazakhstan in the second round.