Last year's US Open runner-up Daniil Medvedev saw off fellow Russian Andrey Rublev in straight sets to reach the semi-finals at Flushing Meadows.

Medvedev, who was beaten by Rafael Nadal in the 2019 final, was dominant on Arthur Ashe Stadium despite needing a medical timeout in the final set.

It means the 24-year-old is yet to drop a set in New York this year.

"It was a very tactical game and I am very happy to go through," he said.

With Swiss great Roger Federer and Nadal absent from New York and the other member of the "big three", Novak Djokovic, disqualified, Medvedev will join a semi-final line-up that is without a Grand Slam title between them.

They will all be hoping to become the first new winner of a men's Slam since Marin Cilic won the US Open in 2014.

A tense opening set was briefly interrupted by a power outage and play was suspended with Rublev leading 6-5.

Rublev then had a 5-1 advantage in the tie-break, but was unable to close out and smashed his racquet on the court as he conceded the first set.

Medvedev broke to make it 4-2 in the second and frustration continued to creep into his opponent's game, with Rublev issued with a code violation for verbal abuse as he went 5-2 behind.

At two sets up, Medvedev was looking comfortable but the 24-year-old began to show signs of cramp and twice needed treatment.

He still looked to be struggling slightly in the tie-break but was able to close out as a Rublev backhand dropped wide at match point.

"It is maybe the first time in almost a year that I actually celebrated my win," he said.

"Because I felt like I could get in trouble, one point decided two sets. Andrey was playing unbelievable, so I am really happy with my win."