British No 1 Cameron Norrie came through in straight sets against young Dane Holger Rune to make the last 16 of the US Open for the first time.
Norrie and 19-year-old Rune had already met twice this season, with the Brit winning on both occasions in close contests, but there was clear daylight between the pair at Flushing Meadows on Saturday with the seventh seed running away to record a comfortable 7-5 6-4 6-1 win.
"Holger is not easy to play. He can go through patches when he's passive and then he can hit very aggressively so you have to be ready for anything," Norrie told Prime Video. "He has great hands and defends really well at times, but I stayed a lot calmer than he did throughout the big moments.
"I feel great. Sometimes you start a little bit tight and you play guys who are not great match-ups for you and you're nervous.
"You get through those ones and you have a lot confidence, feeling the courts a bit better, and then you get put on a stadium court and you feel a little bit more rhythm and you play your way into the tournament. It was good."
Rune, already the highest-ranked Danish man in history and a French Open quarter-finalist this year, accused Norrie of gamesmanship when he protested to the umpire about the Briton catching his ball toss before serving during the second set.
Players are allowed 25 seconds between points but the clock stops when the server throws up the ball, meaning catching the toss buys extra time to reset.
Rune made it clear to the umpire he thought Norrie was deliberately exploiting a loophole in the rules but his protests fell on deaf ears and he was more diplomatic in the press room later.
"I think it's a fine balance," said the teenager. "You have those 25 seconds and the umpire accepts that if you're at one second and you do it you can let it go and take five, 10 seconds to bounce it again and then serve, and then you all of a sudden have 10 seconds.
"It's a bit annoying. I'm not controlling the rules but I think you can do it a couple of times but doing it 10, 15 times is maybe too much."
Responding, Norrie said: "I'm not doing it on purpose. I'd love to go out there and have a perfect ball toss every time and get up there and hit rockets. It can happen sometimes. I'd rather play quick. I like to play quick."
Norrie opened up a 5-3 lead in the first set but hit a wild double fault and then shanked a smash to drop serve, only for Rune to play a similarly poor game and give him a second chance.
The British No 1 looked to have taken control of the second set at 4-1 but Rune was able to apply some late pressure again, forcing Norrie to save two break points at 5-4.
The Dane complained to the umpire about Norrie's ball toss during that game before continuing his protests at the end of the set.
Rune could offer no real resistance in the third with Norrie able to ease to victory and set up a meeting with either Canadian Denis Shapovalov or Russian Andrey Rublev on Monday.
"They're both great players," added Norrie. "They have a lot of experience and they both play big tennis. I feel like it's whoever can stay calmer and play better in the bigger moments. It's going to be a really, really good match and it's going to be tough whoever I play."
Later, Dan Evans goes into his contest with 2014 champion Marin Cilic as a slight underdog but can take confidence from having won their only previous meeting, albeit five years ago at the Australian Open.
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