Taylor Fritz won six straight matches against a weak and frustrated Frances Tiafoe on Friday night at the US Open, finishing victorious 4-6, 7-5, 4-6, 6-4, 6-1 in an all-American match to reach his first Grand Slam final.

The victory of 12th-seeded Fritz over 20th-seeded Tiafoe, a duo of 26-year-olds who are good friends and have known each other since they competed in tournaments for under-14s, earned him a championship showdown with top-seeded Jannik Sinner on Sunday.

Fritz is the first American to appear in a major final since Andy Roddick lost to Roger Federer at Wimbledon in 2009. And if he can beat Sinner, Fritz would become the first American to win a Grand Slam trophy since Roddick won it at the US Open 21 years ago.

From 4-all in the fourth set Friday, Fritz took control when Tiafoe’s hitting and usual confidence deserted him. After a double fault yielded a break to make it 4-0 in the fifth, Tiafoe threw his racket in the trash after more than three hours of play. Fritz repaid the favor by double faulting to end the next game, but broke right back and it was quickly over.

Sinner, a 23-year-old Italian who was acquitted in a doping case less than three weeks ago, earlier on Friday claimed a 7-5, 7-6 (3), 6-2 victory over No. 25 Jack Draper, with both players receiving simultaneous treatment from trainers deep into the 1½-hour second set.

“It was a very physical match, as we can see,” said Sinner, who won the Australian Open in January. “I just tried to stay mentally focused.”

His left wrist was being massaged after he fell during a winning point; Draper required medical attention after vomiting twice in a game that featured temperatures in the 70s and humidity in excess of 60 percent. During that lull in the action, a vacuum cleaner was used to clear the ground behind the baseline, finishing the cleanup job that Draper, a 22-year-old from Britain, was attempting to do himself by wiping up his, er, mess with a towel.

There was no drama whatsoever outside of the actual Tiafoe vs. Fritz match, and the crowd at Arthur Ashe Stadium could have been excused for not knowing who to cheer for in the first semifinal in New York between two American men in 19 years.