Ben Shelton, who won the 144 mph thunderbolt show in the semi-finals of the US Open

Ben Shelton, United States, (AP Photo) Ben Shelton produced another stunning display of power at the US Open, hitting a 144mph (232km/h) serve in his semi-final victory over Frances Tiafoe on Friday.The 23-year-old American’s powerful serve was one of the key factors in his 4-6, 6-3, 6-3, 7-5 victory over second-seeded American Tiafoe, which sent Shelton into his first Grand Slam final.Shelton’s serve became especially decisive after he dropped the opening set. He finished the match with 20 aces and repeatedly put Tiafoe under pressure with his pace.During the second set, Shelton showed how difficult his serve was to master. With new balls in play tied at 3-3, he sent down a 125 mph fastball that forced Tiafoe to raise his racquet almost in self-defense and knocked him backward. Shelton then followed with serves of 144, 139 and 140 mph, the last two leading to aces.The 144 mph serve added another highlight to a remarkable night for Shelton, who had already stunned defending champion Carlos Alcaraz in the quarterfinals.Shelton’s win over Tiafoe also kept alive America’s hopes of ending its 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 the title, will now face top seed and French Open champion Alexander Zverev in Sunday’s final.“I’m going to go for it here and leave it all on the court,” Shelton said. “I hope you come and get back at me. Let’s do it for the US.”Zverev, who defeated 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.“I hope I can’t achieve the American dream on Sunday,” Zverev said.