Casper Ruud reached the US Open semi-finals for the first time on Tuesday, potentially reigniting his bitter feud with Nick Kyrgios.
The Norwegian fifth seed defeated Italy's Matteo Berrettini 6-1, 6-4, 7-6 (7/4) to make his second Slam semi-final of 2022 having finished runner-up to Rafael Nadal at the French Open.
Wimbledon finalist Kyrgios faces Karen Khachanov later Tuesday in his quarter-final.
"That was a better start than I ever had before. Everything was going my way plus Matteo didn't serve as well as he usually does," said Ruud who was 2-5 down in the third set.
"I got a little nervous towards the end of the second set because things were going a little too well.
"You think you can walk on water, which is not possible. The third set was very tough."
The Norwegian broke the Italian five times while saving seven of nine break points.
Ruud raced through the first two sets under the roof of Arthur Ashe Stadium before 2019 semi-finalist Berrettini stopped the rot with a break for 2-0 in the third.
The 23-year-old Ruud saved two set points in the seventh game before going on to dominate the tiebreak.
Kyrgios, who knocked world number one and defending champion Daniil Medvedev out in the third round, is attempting to become the first Australian man to reach the US Open semi-finals since Lleyton Hewitt in 2005.
Khachanov is playing in his third Slam quarter-final but has yet to reach a semi-final.
"I think Nick has taken steps as a player. We all know he's been a huge talent but this year he has proved he can win many matches in a row and it is impressive," said Ruud.
"Obviously he has improved and he will be a dangerous player for sure. Let's see if it will be some drama or not, but I'm ready for anything."
Kyrgios and Ruud's feud started in 2019 when the Australian was defaulted from their clash at the Rome Masters.
He had been penalised a game for swearing at a line judge. Kyrgios was so angry that he threw a chair onto the court, packed his bags, stormed off court and was defaulted.
He was later fined 20,000 euros and docked ranking points.
Ruud called for Kyrgios to be banned from the tour for six months and branded his rival an "idiot".
Kyrgios responded by describing the Norwegian's tennis as "boring".
"Hey @CasperRuud98 next time you have something to say, I would appreciate you say it to my face, I'm sure you wouldn't run your mouth so much after that. Until then I will continue to rather watch paint dry then watch you play tennis."
Kyrgios went on to claim Ruud was "stealing" points by playing in a succession of low-profile claycourt events in order to boost his world ranking.
Despite their contentious history, however, Kyrgios and Ruud played out an incident-free clash at Indian Wells in March which the Australian won in straight sets.