Australian Open champion Stan Wawrinka fought off two set points in the pivotal third set on the way to a 7-5 4-6 7-6(7) 6-2 win over Spain's Tommy Robredo on Tuesday to reach the quarter-finals of the US Open.
After splitting the first two sets, the third-seeded Swiss trailed 6-4 in the third-set tiebreaker but battled back to win 9-7 and closed out the victory over the Spanish 16th seed in the fourth set.
''It was a really tough battle today. It's always tough to play against him, he is always fighting,'' said Wawrinka, who showed his competitive fire with a dive into the stands during a point in the tight confines of Louis Armstrong Stadium.
Wawrinka will play either big-serving Canadian Milos Raonic, the fifth seed, or 10th-seeded Kei Nishikori of Japan in the quarter-finals.