John Isner has secured his place in the fourth round of the US Open after Jiri Vesely was forced to retire in their clash.

The American started the match in positive fashion and was comfortable on his serve, putting pressure on Vesely, before eventually finding the breakthrough to help him take the first set 6-3.

The second proved to be more open as both men had opportunities to break, but Isner displayed his quality by fending off the challenge of the Czech and then managed to secure the break to secure the win 6-4.

Vesley then began to have issues with the heat and was unable to take the court for the third, forcing his retirement from the match and handing the victory to the number 13 seed.

Isner will face Roger Federer in the fourth round of the competition.