New York: Top seed Novak Djokovic saved four set points in a marathon first-set tiebreaker before rolling past Alexandr Dolgopolov of Ukraine 7-6 6-4 6-2 to reach the quarter-finals of the U.S. Open Monday.
The Serb won the opening set decider 16-14 on his sixth set point, cupping his hand over his ear to encourage the Louis Armstrong Stadium crowd`s roars of approval before pumping his fist in joy.
"Winning it was very important," the world number one said. "That was probably the turning point. After that it was a good performance."
Djokovic had his hands full figuring out the unorthodox style of his 22-year-old opponent as well as the swirling winds that swept through Flushing Meadows, but his straight-sets win meant he still has yet to lose a set in the tournament.
"He was changing pace a lot," the Wimbledon and Australian Open champion said. "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.
"That`s why it was crucial for me to win the first set. After, I felt a bit more relaxed."
Dolgopolov, who won his first tournament this year and his first matches at a U.S. Open, said he felt good in his first ever match against Djokovic.
"I felt comfortable on the court," he said. "I think I just need to get my first serve, for sure. You can`t play a great returner like that, serve around 40 percent, that`s impossible.
"I was having fun just stepping on the court, so much people, good court, playing Novak. I made a good result in the tournament. I was just happy to play tennis. I gave a bit of a fight, but I still need some work."
The victory improved Djokovic`s 2011 record to a remarkable 61-2 and took him through to a 19th straight grand quarter-final.
His next opponent is his good friend and Davis Cup team mate Janko Tipsarevic, who beat Juan Carlos Ferrero of Spain in a nearly four-hour struggle.
"It means there`s going to be at least one Serbian in the semi-finals, which is great for our country," Djokovic said.
"I think this is the first time I play Janko in a grand slam. We are great friends. It`s not going to be easy to play him, but look, it`s the quarter-finals and we both want to win."