World number one Novak Djokovic weathered a first-set storm to subdue Alexandr Dolgopolov 7-6 (16/14), 6-4, 6-2 on Monday and reach the quarter-finals of the US Open.
Djokovic set up an all-Serbian last-eight clash with Janko Tipsarevic, but first he had to quell the challenge presented by world number 23 Dolgopolov on the windy Louis Armstrong Stadium.
Djokovic, who has lost just two matches this year and claimed the Australian Open and Wimbledon titles as he surged to the top of the rankings, needed six set points -- and had to save four -- to claim the first-set tiebreaker.
Dolgopolov, a 22-year-old Ukrainian enjoying the best year of his career, showed no fear against tennis' dominant player, using his speed and a variety of pace to keep Djokovic on the hop.
"I was confused on the court the first set," admitted Djokovic, who nevertheless notched his 61st match victory of the year with relative ease.
"I think it was exciting for the crowd to watch because it was very close," he said. "But I think it was game-wise an ugly first set because I wasn't happy with the way I played.
"He was changing pace a lot. He was always sending me a different ball. It was really hard for me to adjust to it because of the conditions that we played in." Ugly or not, the packed house on the Louis Armstrong Stadium, the main court at Flushing Meadows before the 22,000-seat Arthur Ashe Stadium was built, loved it. "I was happy to experience the Armstrong court again," he said.