Ben Shelton smashes 158 mph serve, sets new Grand Slam record at US Open

Ben Shelton produced another stunning display of power at the US Open, hitting a 158 mph (254 km/h) serve during his semifinal victory over Frances Tiafoe on Friday.The 23-year-old American's thunderous delivery came as he continued to turn his serve into one of the biggest weapons of his run at Flushing Meadows. Shelton defeated fellow American Tiafoe 4-6, 6-3, 6-3, 7-5 to reach his first Grand Slam final.Shelton's serve was particularly decisive after he lost the opening set. He finished the match with 20 aces and repeatedly put Tiafoe under pressure with sheer pace.During the second set, Shelton showed just how difficult his serve was to handle. With the new balls in play at 3-3, he sent down a 125 mph delivery that forced Tiafoe to get his racket up almost in self-defence and knocked him backwards.