Ben Shelton, of the United States, (AP Photo)

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. Shelton then followed it with serves clocked at 144, 139 and 140 mph, with the final two resulting in aces.The record-breaking 158 mph serve added another highlight to a remarkable night for Shelton, who had already stunned defending champion Carlos Alcaraz in the quarterfinals.Shelton's victory over Tiafoe also kept alive America's hopes of ending a long wait for a men's Grand Slam champion. The host nation has not had a men's major winner since Andy Roddick lifted the US Open trophy in 2003.Shelton, who was less than a year old when Roddick won that title, will now face top seed and French Open champion Alexander Zverev in Sunday's final."I'm going for it here, and I'm going to leave it all on the court," Shelton said. "I hope you guys come and back me. Let's do it for the USA."Zverev, who beat Karen Khachanov 6-3, 7-6 (7), 7-6 (6) in the other semifinal, is aware of what a Shelton victory would mean for American tennis."Hopefully I can not make the American dream come true on Sunday," Zverev said.