Richard Ramsay is in line to become Britain's first US amateur champion in 95 years after beating American Webb Simpson one up in the semi-finals at Hazeltine National in Chaska, Minnesota yesterday.
The 23-year-old, who represented Britain and Ireland at last year's Walker Cup, will face American, John Kelly, in Sunday's 36-hole final.
Kelly, 21, came back from one down after four holes to defeat Canada's Ryan Yip 2 and 1.
Scot Ramsay, winner of last year's Irish amateur strokeplay championship, held off a late surge by Simpson after leading by three with seven holes to play.
The 21-year-old American cut the deficit to one after winning the 12th and 14th holes, trailed by two after losing the 15th and was awarded the 16th after his opponent grounded his club in a hazard.
However, the Scot clinched the match on the final green after the last two holes were halved.
"I know the shots that I've got in the bag and I wasn't making any mistakes," Ramsay told reporters of his strategy after losing the 16th hole. "I know what I can do. He's got to beat me over the last two holes."
Ramsay is bidding to become the first British winner since Harold Hilton in 1911. He is the first Briton to reach the final since Jack McLean in 1936.
Last year, Italy's Edoardo Molinari became the first European champion since Hilton with a 4 & 3 win over American Dillon Dougherty at Merion Golf Club in Ardmore, Pennsylvania.
Kelly, who went ahead for the first time against Yip with a birdie on the downhill par-four 10th, was delighted with his performance.
"I kept trying to tell myself that I'm a good enough player to be here, and I believed it," he said. "As long as I'm believing that I can play for the trophy, that's great."
The winner of the US amateur earns exemptions into next year's US Masters, US Open and British Open, as long as he retains his amateur status.