For the first time since 2005, a Grand Slam men's semifinal will feature two Americans.

On Tuesday, Taylor Fritz defeated Alexander Zverev in the second consecutive Grand Slam, reaching his first career major semifinal.

Just hours later, Grigor Dimitrov, Frances Tiafoe's quarterfinal opponent, had to retire in the fourth set due to injury, paving the way for Tiafoe to advance to his second U.S. Open semifinal in three years.

The two friends—long viewed as the future of American tennis—will square off on Friday, with history on the line. The winner will become the first American to reach a Grand Slam final since 2009 (Andy Roddick).

In the women's draw, Emma Navarro defeated Paula Badosa, reaching her first career major semifinal in just her third trip to the year's final major.

On Thursday, the 23-year-old will face her hardest task yet: world No. 2 Aryna Sabalenka, who has won two of the three last Grand Slams on the hard-court surface and is coming off a dominant win against No. 7 seed Qinwen Zheng.

Here are the top reactions from Tuesday's play.

Tuesday U.S. Open Results

Men's Singles

No. 12 Taylor Fritz def. No. 4 Alexander Zverev, 7-6(2), 3-6, 6-4, 7-6(3)

No. 20 Frances Tiafoe def. No. 9 Grigor Dimitrov, 6-3, 6-7(5), 6-3, 4-1 (retired)

Women's Singles

No. 2 Aryna Sabalenka def. No. 7 Qinwen Zheng, 6-1, 6-2

No. 13 Emma Navarro def. No. 26 Paula Badosa, 6-2, 7-5

Taylor Fritz Earns Biggest Victory of His Career

For the first time in his career, Taylor Fritz is advancing to the semifinals of a Grand Slam.

The 26-year-old American defeated Alexander Zverev for the second consecutive Grand Slam in a four-set thriller.

Down the stretch, Fritz's play was remarkable.

In the fourth set, the No. 12 seed won 20 of 21 points on his first serve and surrendered only seven total points in his service games.

Furthermore, he was able to hang around with Zverev's backhand, considered one of the best on the ATP tour, while troubling the German with his blistering forehand.

The top-seeded American has won at least 80% of points on the first serve in each match on his way to the semifinal.

On Friday, Fritz will face either Frances Tiafoe or Grigor Dimitrov in the semifinals, looking to continue his impressive run.

Frances Tiafoe Back in U.S. Open Semifinals

For the second time in three years, Frances Tiafoe is back in the semifinal round of the U.S. Open.

The 26-year-old American led Grigor Dimitrov two sets to one before the Bulgarian aggravated a previous hamstring injury, ultimately forcing him to retire.

Over the course of the night, Tiafoe was impressive against Dimitrov's second-serve victory, winning 37 of 59 points.

Furthermore, the No. 20 seed remained calm and collected on his own, winning 74% of points on his first serve while saving three of four breakpoints.

On Friday, Tiafoe will play the biggest match of his career against Taylor Fritz.

The winner will become the first American to reach a Grand Slam final since 2009.

Aryna Sabalenka Reaches Fourth Straight U.S. Open Semifinal

What will it take for an opponent to defeat Aryna Sabalenka?

The world No. 2 dispatched No. 7 seed Qinwen Zheng in straight sets, limiting the recent Olympic gold winner to just three games total.

The two-time Grand Slam champion has dropped just one set this entire U.S. Open.

Meanwhile, her return game continues to stand out.

In fact, Sabalenka has won at least 52% of points on every opponent's second serve dating back to the first round.

For the fourth straight year, the No. 2 seed is back into the U.S. Open semifinals.

On Thursday, she'll face homegrown favorite Emma Navarro, looking to reach the final for the second consecutive year.

Emma Navarro Reaches First Career Major Semifinal

Emma Navarro is moving on to her first career Grand Slam semifinal.

After defeating Paula Badosa in a dominant first set, the No. 13 seed found herself in serious trouble in the second set.

Down 5-1 in the second set, Navaroo was on her way to having to play a winner-take-all third set.

Then, the 23-year-old changed her game plan.

Instead of attempting to match Badosa's heavy groundstrokes, Navarro switched her game plan by focusing on consistency, forcing her opponent to make the first mistake and winning the next six games.

Navarro has now defeated back-to-back difficult opponents in No. 3 seed Coco Gauff and most recently Paula Badosa, further reinforcing just how much progress she's made in the past year.

In the semifinals, the first-time semifinalist will face either Aryna Sabalenka or Qinwen Zheng.