PIX: Thiem tames De Minaur; to take on Mededev in semis

Second seed Dominic Thiem delivered a sublime performance to dismantle Australian Alex de Minaur 6-1, 6-2, 6-4 on Wednesday and canter into the semi-finals of the US Open.

Thiem needed a little over two hours to record the win under the closed roof of Arthur Ashe Stadium despite being put under constant pressure by De Minaur, who is nicknamed 'Demon' and known for his never-say-die attitude and speedy court coverage.

De Minaur advanced to the net at every opportunity to disrupt Thiem's baseline game and while the plan worked initially the 27-year-old Austrian adjusted and started finding winners past his advancing opponent.

De Minaur's serve was vulnerable all night and Thiem, who amassed 43 winners, converted seven of his 13 breakpoint opportunities. De Minaur could take only two of the seven chances he had to break Thiem's serve.

"I had a great feeling from the first moment on," Thiem said during his on-court interview. "My feeling was that the first set, not until the second time I broke him, was really intense. Very long rallies.

"The second looks a lot easier than what it was on the scoresheet. The third set I lost a little bit of the momentum and energy and he came back great."

Thiem, the highest surviving seed at Flushing Meadows, had beaten the Australian in their two previous encounters and started their third meeting on a brisk note, breaking De Minaur's serve three consecutive times to win the opening set.

De Minaur started on a more positive note in the second, winning 11 straight points on serve to lead 40-0 in the fifth game with the score tied at 2-2.

However, Thiem fought his way back into the game and broke the Australian to lead 3-2, then won three straight games to take the set.

The Austrian's early lead in the third set evaporated as De Minaur rallied to level things but a second break of serve sealed the match for Thiem.

"The match was going a bit flat from both of us," Thiem added. "It's not easy in an empty stadium and it being so late. We both got back the energy ... and there was an amazing level where we both switched it on.

"But with two sets in my back pocket it was a little bit easier for me."

Thiem will meet Russian Daniil Medvedev for a place in his fourth Grand Slam final.

Medvedev beats childhood friend to reach semis

Daniil Medvedev continued his march towards a first Grand Slam title on Wednesday, powering into the US Open semi-finals with a clinical 7-6(6), 6-3, 7-6(5) victory over childhood friend Andrey Rublev.

The first Russian duo in the quarter-finals at a Grand Slam since Igor Andreev and Nikolay Davydenko at Roland Garros in 2007, Medvedev showed no fear during a ruthless display that sent him through to the last four without losing a set.

No player in the Open Era has won the US Open men’s title without dropping a set.

With Roger Federer and Rafa Nadal missing, and top seed Novak Djokovic having been disqualified for hitting a line judge with a ball, Medvedev showed why he is now the bookmakers' favourite to win in New York.

The third seed never gave Rublev a break chance in the entire match while hammering down 16 aces.

"I felt like I could get in trouble so I was very happy with the win," said Medvedev, who called for the trainer to work on his shoulder during the match. "One point decided two sets so it was a tough match."

Medvedev, who lost an epic five-setter to Nadal in last year's final, will face second-seeded Austrian Dominic Thiem in the semis.

Having competed against each other since they were young kids the practice partners knew exactly what to expect and a grinding 63-minute opening set offered no surprises or breaks.

Rublev, who had never taken a set off Medvedev in three career meetings, looked poised to end that run when he went 6-3 up in the tiebreak but the 10th seed was unable to close the deal as Medvedev swept five straight points.

"There is more chance you lose a set down 5-1 than win it," said Medvedev. "Usually he is very aggressive but today he was trying to put the ball in the court more so I tried to be more aggressive and really go for it even in the third set tiebreaker and it worked out for me."

The collapse sent the volatile Rublev into a rage, smashing his racket, throwing towels and yelling at his coach and the 22-year-old never recovered.

Medvedev maintained pressure in the second, registering the only break of the match to nose in front 4-2 on way to a commanding 2-0 advantage.

Rublev continued to battle but Medvedev gave him no openings and closed out the match 7-5 in a tiebreak.