NEW YORK, Aug 31 (Reuters) - Holger Rune lost his maiden Grand Slam match to Novak Djokovic on Tuesday but the brave Dane won over the fickle New York crowd at Arthur Ashe Stadium by refusing to retire despite struggling with painful cramp. Djokovic, a three-times U.S. Open champion and bidding to complete a rare calendar-year Grand Slam on the Flushing Meadows hardcourts, is a popular headliner on the New York stage. But on Tuesday it was the dashing 18-year-old newcomer being showered with cheers for his plucky effort in a 6-1 6-7(5) 6-2 6-1 loss to the world number one. "I never felt anything like this," said Rune. "It was unbelievable feeling staying there. "I tried to give the crowd something, fight for every point, be pumped and everything. "I mean, the crowd was unbelievable. I couldn"t have asked for more." The match got underway amid a somewhat flat atmosphere inside Arthur Ashe Stadium but the crowd were chanting the little-known Dane"s name after he stunned Djokovic to win the second set. Embracing his moment on tennis"s biggest stage, Rune brought energy and a captivating swagger to the contest that endeared him to the audience. When Rune broke Djokovic in the second set the teenager turned to the crowd and pumped his fist, drawing a huge roar. But the biggest applause came later as Rune hobbled around the court with cramp, gutting it out to a predictable defeat but winning the respect of the crowd. "I never want to stop matches. I want to complete them," said Rune. "I want to try to see if I can find solution. "Against a player like Novak it"s tough if you can"t move 100%. Even if you move 100%, you"re not sure you"re going to beat him. "It"s tough if you have no legs."