World Number three Roger Federer survived a first round scare from Frances Tiafoe as the Swiss ground out a 4-6 6-2 6-1 1-6 6-4 victory over the American teenager before a raucous crowd at the U.S. open.

Federer looked more relieved than overjoyed when Tiafoe's forehand found the net on match point to keep his hopes of a 20th grand slam title alive.

Federer, who has won this year's Australian open and Wimbledon, found his groove once he broke Tiafoe to take a 3-1 lead in the second set and reeled off nine of the next 10 games.

In the deciding set, Tiafoe saved a match point at 3-5 down before breaking Federer's serve with a brilliant forehand pass, but Federer came back to break serve and take the match in the next game to win.