NEW YORK (AP) ― Through a pair of back-and-forth sets, Novak Djokovic and Andy Murray put on a display befitting a matchup of past U.S. Open champions.

They tracked down would-be winners and somehow got them back, prolonging points that involved 10 or 20 strokes or more, extended by Djokovic’s slides and splits or Murray’s gifted anticipation. After one 30-shot masterpiece on his way to victory, Djokovic raised his right fist, bellowed, “Come on!” and windmilled his arms to rile up the crowd.

Eventually, the physically demanding action proved too much for a fading Murray, and Djokovic pulled away to win 7-6 (1), 6-7 (1), 6-2, 6-4 and reach the tournament’s semifinals for the eighth consecutive year.

“I knew coming into tonight’s match that it’s going to be tough, that he’s going to go for his shots, and the more aggressive one would win it,” the No. 1-ranked and No. 1-seeded Djokovic said. “I’m glad I managed to stay fit in the end and pull it through.”

It took a while for him to push out front in a 3-hour, 32-minute match that ended after 1 a.m. Thursday.

Asked in an on-court interview to look ahead to facing 10th-seeded Kei Nishikori of Japan in Saturday’s semifinals, Djokovic joked: “My thoughts are just directed to sleeping right now.”

That drew guffaws from spectators, and he continued: “Or party. What do you say? Let’s party. I think my coach right there would chase me with a little baseball bat if he saw me going to the city to party right now.”

Djokovic broke the eighth-seeded Murray to go up 3-1 in the third set, then fended off a pair of break points in the next game. On the first, Murray sailed a backhand long to end a 28-stroke point, then leaned over and put a hand on his knee. On the second, he dumped a forehand into the net, then slammed his racket against his right thigh and yelled.

Soon, Murray was turning to his box to say, “Nothing in the legs.” In the fourth set, a trainer came out to deliver a heat pack to Murray.