American 10th seed John Isner is into the third round of the men's Olympic singles thanks to a straight-sets win over Tunisia's Malek Jaziri.
With neither player dropping serve in the opening set Isner romped to a 7-1 victory in the tie-break.
World number 11 Isner was rarely troubled in the second as he saw off his opponent 6-2.
Isner will now take on either Serbian seventh seed Janko Tipsarevic or Germany's Philipp Petzschner in the next round.