Roger Federer required a wake-up call from debutant Lloyd Harris before beating the South African in four sets to reach the second round at Wimbledon. World number 86 Harris, playing in his first Grand Slam, sent the Centre Court crowd into shock when taking the first set 6-3, but Federer recovered in style to seal a 3-6 6-1 6-2 6-2 win. "I struggled early on, felt a bit frozen, my legs weren't going, he was hitting it big and things happened very quickly. He did really well and kept me nervous. The break in that second set turned things round, but it took a big effort today," Federer said. "This is where experience kicks in. I had time to figure it out and manage the nerves. Credit to him and swinging big at the beginning. I was a bit disappointed I couldn't play well from the get go but this court has some great memories for me." Chasing his ninth title at Wimbledon, second seed Federer вЂ“ who last won here two years ago вЂ“ appeared to be going through the motions before he stumbled in the sixth game of the opening set. And after Harris valiantly broke the Swiss, the 22-year-old held his nerve to close out the opening set after just 29 minutes. After discovering he had a match on his hands, Federer turned the screw, breaking twice to level up at one-set all. The match continued at a remarkable pace, only passing the hour-mark midway through the third set as Federer again broke twice without offering his opponent a way back. Harris was visibly struggling in the fourth set, often stretching between points, and his resolve ended when Federer broke in the third game before closing it out to win after one hour and 50 minutes on court. Briton Jay Clarke awaits Federer in the second round, with the world number 169 recording a four-set win against Noah Rubin.