Second seed Dominic Thiem edged a first-set tiebreak before turning up the heat to romp into the US Open quarter-finals with a resounding 7-6(4), 6-1, 6-1 victory over Canadian youngster Felix Augur-Aliassime at Arthur Ashe Stadium on Monday.
Top seed Novak Djokovic's disqualification on Sunday for striking a line judge with a ball has left Thiem as one of the favourites and the Austrian gave a composed performance to reach the last eight in New York for the second time in his career.
He was helped in his quest for a maiden Grand Slam title by a below-par performance from the talented Augur-Aliassime, who beat Andy Murray in round two but was well off the pace against Thiem, making 51 unforced errors versus the second seed's 24.
After a cagey opening, Thiem drew first blood, breaking his 20-year-old opponent to take a 3-2 lead in the first set after a pair of unforced errors by Augur-Aliassime.
Thiem consolidated with a hold to love, but stumbled in the 10th game, opening with a double fault and offering two break points after a couple of loose backhands before surrendering his serve with another error to allow his opponent to draw level.
Augur-Aliassime started the tiebreak with an ace, but Thiem regained the initiative to open up a 3-1 lead and sealed the set after the Canadian's 24th unforced error.
"The first set was really important," Thiem said in an on-court interview. "I was really nervous before the match.
"I had a chance to serve for the first set, missed it pretty poorly but then the tiebreak was really good. I started to miss less and less."
The Austrian broke Augur-Aliassime's serve again at the start of the second set and did not look back, delivering an ominous statement of intent as he dominated the youngster and ran away with match.
"I've started to find that mix again, which I had last in Australia, I guess," added Thiem, who lost to Djokovic in the Australian Open final. "The perfect mix of offence and defence.
"I'm really not missing a lot, pulling a lot of returns back in play. It was my best match so far and I'm going to try to keep that form for the next one."
Thiem won 74% of his first serve points and was near flawless at the net, while also sending down 22 winners as he wrapped up the contest in a shade over two hours.
Next up for the 26-year-old is a quarter-final clash with Australian youngster Alex de Minaur, who he has beaten in both of their previous meetings, including in the opening round at Flushing Meadows three years ago.
Australian De Minaur beats Pospisil to reach last eight
Australian young gun Alex de Minaur tamed Canada's Vasek Pospisil 7-6(6), 6-3, 6-2 at the US Open on Monday to ease into his first Grand Slam quarter-final.
The first Australian to reach the men's last eight at Flushing Meadows since John Millman in 2018, the 21st seed will take on second-seeded Austrian Dominic Thiem.
When the US Open started neither promising 21-year-old De Minaur nor 30-year-old Pospisil, who grabbed more attention in recent weeks as Novak Djokovic's sidekick in starting a new players association, would have been tipped as a major winner.
But with Djokovic disqualified on Sunday after striking a line judge in the throat with a ball, Roger Federer and Rafa Nadal not at Flushing Meadows and Andy Murray suffering an early exit, the chances of de Minaur winning the title have grown.
With the stakes a little higher, the opening set unfolded like the first round of a prize fight with both players probing for openings and neither managing a single break chance.
In the tiebreak it was Pospisil who had looked poised to land the first blow by going up 6-2, but De Minaur sweept the next six points to grab a 1-0 lead.
"That first set was crucial," said De Minaur. "I think it was just a couple of things going his way and then my way.
"I went down 6-2 but I don't think I played a bad tiebreak I was just unlucky here and there.
"I just tried to stay calm, do my thing."
After that effort the 94th ranked Canadian could only muster token resistance, with De Minaur securing an early break in the second and third sets and never allowing Pospisil a chance to get back into the match.
Medvedev mauls Tiafoe to reach quarter-finals
Daniil Medvedev stormed into the US Open quarter-finals with a dominant 6-4, 6-1, 6-0 win over a listless Frances Tiafoe at Arthur Ashe Stadium on Monday.
The Russian third seed, who lost an epic five-set final to Rafa Nadal at Flushing Meadows last year, barely broke a sweat in the evening match as American Tiafoe's resistance crumbled after going down a break in the second set.
With top seed Novak Djokovic disqualified on Sunday for hitting a ball into a line judge, Medvedev is now backed to win his first Grand Slam title in New York.
He will face 10th seed and fellow Russian Andrey Rublev for a place in the semi-finals.