Andy Murray showed the fighting qualities that he was renowned for in his prime, battling back from two sets down to progress to round two of his comeback Grand Slam at the US Open. Playing in his first singles Grand Slam in 18 months because of injury and the coronavirus pandemic, Murray dug deep to prevail in a 4hr 39min bruiser against Japan's Yoshihito Nishioka, winning 4-6, 4-6, 7-6 (7/5), 7-6 (7/4), 6-4. "That's by far the most tennis I've played since 2019," said Murray, who lost in five sets in the first round of the 2019 Australian Open to Roberto Bautista Agut. "At the beginning of the match I was apprehensive about playing a long match because I hadn't played one in a while. "I was sort of pacing myself. Once I got two sets down I had to start putting the after-burners on and managed to get through." Murray will play 15th seed Canadian Felix Auger-Allassime in the second round. Murray's comeback appeared to be heading for disaster when he went 3-1 down in the third set, appearing all-but-certain to be heading for an embarrassing straight-sets exit. But showing the grit and determination that led him to three Grand Slam wins during his peak, Murray hauled himself into a 5-4 lead before taking the set on a tiebreak. By then, Murray was playing more aggressively, forcing Nishioka on to the back foot and into errors of his own. The Scot's fist pumps became more pronounced and his roars of "come on!" more audible in spectator-free Arthur Ashe Stadium as he took the fourth set. The first four games of set four went to serve until a Murray double fault put him a break down. Murray immediately broke back though, a delicate backhanded lob from deep making the score 3-3, before breaking again for game, set, match. Murray, the 2012 US Open champion, was competing in a Grand Slam singles match for the first time since last year's Australian Open when there was lots of talk of him retiring. The past three years of his career have been ravaged by injury and he has fallen to 115 in the ATP world rankings. Murray said he "did all right physically" but felt "tired". He added that his big toes were "pretty beat up" and that he hoped organisers would grant him special permission to have an ice bath, with access restricted due to strict coronavirus measures. "They said it was for emergencies. For me this is an emergency right now. I'll ask and see if they'll allow me to use the ice bath. If not I'll try to get back to the hotel as quickly as I can," he said. Murray had career-saving hip surgery in 2019, his second hip operation, before suffering another setback with a pelvic injury at the Davis Cup last November. That, combined with the pandemic shutdown, kept him out of competition until the ATP Western and Southern Open in New York this past week, where he reached the last 16. The comeback made it 10 career wins from two sets down, tying Roger Federer's record among active players. "Hip hip hooray," tweeted Murray's mother, Judy Murray. Murray was handed a wild card for the US Open after narrowly missing out on direct entry. He is competing at the Flushing Meadows Slam for the first time since 2018.