Taylor Fritz became the first American man since 2009 to reach a Grand Slam final on Friday, setting up a US Open title showdown against world number one Jannik Sinner.

Fritz, the world number 12, twice fought back to defeat compatriot Frances Tiafoe 4-6, 7-5, 4-6, 6-4, 6-1 in his semi-final.

Australian Open champion Sinner became the first Italian man to make the New York final with a 7-5, 7-6 (7/3), 6-2 win over an ailing Jack Draper of Britain.

"He overwhelmed me at the start and I was freaking out a little," said 26-year-old Fritz after securing victory with a 16th ace.

"I just told myself to stay in it, hold serve and apply scoreboard pressure.

"I did all I could to stay in it. If I hadn't have done that I'd regret it forever. In the final, I will come out and give it everything."

Andy Roddick was the last American to make a men's singles final at the Slams at Wimbledon in 2009. He was also the last man from the country to capture a major title when he won the 2003 US Open.

Fritz was just five years old at the time.

Tiafoe was the better player for large parts of the semi-final but after dumping a lazy drop shot into the net to surrender the fourth set, his game fell apart.

"It's tough to swallow, it's going to hurt," said Tiafoe.

Earlier, in a gruelling three-hour match, Draper, the first British man in the semi-finals since Andy Murray won the title in 2012, was undone by 10 double faults and 43 unforced errors.

He also vomited on the court, blaming anxiety for the illness.

"Jack and I know each other very well, we are great friends off court," said Sinner, who unleashed 43 winners in the match where he also injured his wrist in a nasty fall.

"It was a very physical match. He's so tough to beat so I'm excited to be in the final."

The 23-year-old Sinner added: "In the final, it will be a very tough challenge. I'm happy to be in that position because if you are in the final on a Sunday it means you are doing an amazing job."