PIX: Fritz stuns Zverev, to face Tiafoe in US Open semi-finals

Images from the US Open men's singles quarter-finals at Flushing Meadows, New York, on Tuesday.

Taylor Fritz of the United States prevailed 7-6(2), 3-6, 6-4, 7-6(3) in a gripping slugfest against fourth seed Alexander Zverev at Arthur Ashe Stadium on Tuesday to move into the US Open semi-finals for the first time.

The United States have not had a men's champion on home turf since Andy Roddick 21 years ago and Fritz's victory over the former runner-up raised hopes of an American victor at Flushing Meadows.

Fritz beat German Zverev on grass at Wimbledon in an epic five-setter and this time had the added boost of the home crowd being firmly on his side as the 26-year-old US number one marched into the last four at a Grand Slam for the first time.

"I've had a lot of looks at quarter-finals over the past couple of years and today just felt different," said Fritz, who had fallen at the quarter-final hurdle at majors four times before.

"I really felt like it was my time to take it a step further and it's only fitting I'm doing it here on this court at the Open in front of this crowd," added the 12th seed.

There was little to separate them in the opening set when they traded blows from the baseline.

But when the two towering players approached the net, the fans were thoroughly entertained by a mixture of drop shots and winners as they second-guessed each other.

Zverev found himself in a hole when he was 0-40 down while serving to stay in the set but the German eventually recovered to force a tiebreak.

But Fritz was on the up and as Zverev floundered with his forehand and desperately sought answers from his box, the American took the set with an emphatic overhead smash at the net.

Zverev bounced back with a different racquet, producing one of the shots of the tournament when he fired a return from out wide over the net post that curled back and landed on both the side and base lines, celebrating the point with his arms outstretched.

That put a spring in Zverev's step and he broke at 4-3 before serving out the set to level the match, but Fritz returned the favour early in the third when he converted his first break point before racing into a 3-0 lead.

Although Zverev clawed his way back, he was once again forced to save set points after some nervous errors before Fritz finally took the third set when the German found the net as the crowd erupted.

With no breaks on offer in the fourth, Fritz got the upper hand in the tie-break as Zverev once again faltered on crucial points before the American notched one of the biggest wins of his career.

Fritz will play either Bulgarian veteran Grigor Dimitrov or fellow American Frances Tiafoe in the semi-finals.

"I know the crowd would really want to see me and Frances so we get an American in the final," Fritz said.

"I guess we'll see what happens, but either way I'll be ready to go."

Tiafoe reaches US Open semi-finals after Dimitrov retires injured

American Frances Tiafoe reached the US Open semi-final for the second time in three years on Tuesday after Bulgarian Grigor Dimitrov from their match with a leg injury while trailing 6-3, 6-7(5), 6-3, 4-1.

Tiafoe with next meet 12th seed Taylor Fritz in an all-American clash with both players aiming to break a 21-year U.S. men's major drought in a tournament where many of the top contenders were eliminated early on.

Ninth seed Dimitrov, who had to retire with a groin injury during his fourth round tie against Daniil Medvedev at Wimbledon this year, left after the third set for medical treatment and slogged through a few games in pain as his team urged him to retire.

Tiafoe had a muted celebration and offered his opponent an embrace at the net, with the crowd already starting to shuffle out of Arthur Ashe Stadium.

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

Tiafoe was in superb form as he broke his opponent with a perfectly placed backhand winner in the fifth game and got another break on the fourth set point when Dimitrov whacked a forehand into the net.

It looked as though Tiafoe might run away with it as he went up 4-1 in the second set but Dimitrov broke back in the seventh game as the American’s unforced errors began to pile up.

Dimitrov won four points in a row to go up 6-3 in the tiebreak but nearly let it slip through his fingers with a pair of double faults before Tiafoe handed it to him on set point with a double fault of his own.

Down a break in the third set, Dimitrov winced after stepping awkwardly along the baseline in the final game and a double fault gifted Tiafoe the set for a 2-1 lead.

Dimitrov limped off court to receive treatment from the physio before the fourth set and was shaking his head as he moved awkwardly around the court in the first game of the final frame.

Tiafoe, the 20th seed, faces the biggest match of his life career against Fritz and will look to get the better of another American after taking out Ben Shelton in a five-set, third-round thriller.

"I can't be more excited," said Tiafoe.

"I know we're two Americans but I hope you're with me come Friday.