He defied his 37 years to reach an acutely-angled Kyrgios slice and flashed a victor around the post of the net. "Nearly got to the point where I wanted him to start making shots like that, and I finally got it", Kyrgios said.
The No.2 seed was leading two-sets when he produced a truly outrageous victor.
"I think if he breaks there he probably runs away and wins that first set", Federer said.
The match got off to a promising start with neither player able to gain an advantage.
"The 23-year-old Australian mouthed 'Oh my god!" before trying to congratulate Federer, who allowed himself a sly smile, from across the net.
Nick Kyrgios views Roger Federer as the "ultimate role model" to anyone who harbours ambitions of playing tennis and admits he should "take a leaf out of his book", while he admitted he's open to the possibility of adding a mentor figure to his team going forwards. "When he gets in front, there's not much you can do".
Switzerland's Federer may well have decided the match when serving at 3-all, love-40, less than 20 minutes into his game against controversial Australian Kyrgios on Sunday morning (NZT). No. 4 Angelique Kerber and No. 5 Petra Kvitova - owners of a combined five Grand Slam titles - exited Saturday, both at Louis Armstrong Stadium, the same new arena where No. 1 Simona Halep and No. 2 Caroline Wozniacki were beaten earlier in the tournament. Federer was among those critical of the umpire's conduct.
Aretha Franklin to be remembered, mourned at funeral service in Detroit
Amid the sadness of these days, Robinson can find uplift - and believes Franklin's legacy is secure. The singer, known as the Queen of Soul, died earlier this month of pancreatic cancer.
Midway through the third set with the game tied at 3-3, Kyrgios thought he caught the 37-year-old out with a deft drop shot.
Kaia Kanepi, of Estonia congratulates Serena Williams after their fourth round match of the U.S. Open tennis tournament.
It was another Grand Slam disappointment for Zverev, touted as the youngster most likely to end the major dominance of Federer, Djokovic and Nadal.
Federer also regarded his point as "a special one".
In all just three of the top 10 women made it through to the fourth round, although Kerber didn't blame a domino effect for her departure.
"I'm going to say something that's going to be quite contrarian here", Courier said on the Tennis Channel. When a reporter asked her if she remembered the last time she had double-bageled, she said, "Yes, it was you, in my dreams".
Federer, who is seeded second at Flushing Meadows, admitted that it was one of the best shots of his career.
Suarez Navarro, seeded 30th, next faces 2006 champion Maria Sharapova, who defeated 2017 French Open victor Jelena Ostapenko 6-3, 6-2. But, he may need to step out of his comfort zone and play more aggressively if he wants to win this match.