Tiafoe sets up all-American US Open semi-final with win over injured Dimitrov

Frances Tiafoe of the United States, aged 26, advanced to the semi-finals of the US Open for the second time in three years on Tuesday, following the retirement of Bulgarian player Grigor Dimitrov, 33, due to a leg injury while trailing with scores of 6-3, 6-7, 6-3, 4-1.

Tiafoe is set to face 12th seed Taylor Fritz in an all-American showdown, with both athletes striving to end a 21-year drought for American men in major tournaments, particularly in a competition where several top contenders were eliminated early.

Ninth seed Dimitrov, who had previously retired due to a groin injury during his fourth-round match against Daniil Medvedev at Wimbledon this year, sought medical attention after the third set and continued to play through discomfort, despite his team's encouragement to withdraw.

Tiafoe's celebration was subdued as he embraced his opponent at the net, while spectators began to exit Arthur Ashe Stadium.

"It was a really, really high-level match," Tiafoe remarked. "Obviously, I didn't want to end it like that."

Demonstrating exceptional skill, Tiafoe broke his opponent with a precisely executed backhand winner in the fifth game and secured another break on the fourth set point when Dimitrov sent a forehand into the net.

Tiafoe appeared poised to dominate as he led 4-1 in the second set, but Dimitrov responded by breaking back in the seventh game as Tiafoe's unforced errors began to accumulate.

Dimitrov won four consecutive points to take a 6-3 lead in the tiebreak but nearly squandered his advantage with two double faults, ultimately benefiting from a double fault by Tiafoe on set point.

After experiencing a break in the third set, Dimitrov grimaced following an awkward step along the baseline during the final game, resulting in a double fault that allowed Tiafoe to secure the set and take a 2-1 lead.

Dimitrov then limped off the court to receive treatment from the physiotherapist prior to the fourth set, visibly shaking his head as he navigated the court with difficulty during the opening game of the final set.

Tiafoe, seeded 20th, is preparing for the most significant match of his career against Fritz and aims to triumph over another American opponent after defeating Ben Shelton in a thrilling five-set encounter in the third round.

"I couldn't be more thrilled," Tiafoe expressed. "Although we are both Americans, I hope you will support me this Friday."