Nick Kyrgios described toppling Roger Federer as definitely the greatest win of his career, former pro Scott Draper labelling him "one out of the box" as the 20-year-old prepares to be seeded at a grand slam for the first time.
Kyrgios' 6-7, (2-7), 7-6, (7-5), 7-6, (14-12) win at the Madrid Masters over his childhood idol continued his reputation for lifting against the modern greats, adding to his fourth-round boilover against Rafael Nadal at Wimbledon last year.
It virtually guarantees Kyrgios, who turned 20 last week, his first Grand Slam seeding at the French Open beginning May 19.
Ranked 35 in the world, Kyrgios will eclipse his previous best ranking of 34 and ensure he avoids the big names early at Roland Garros.
Kyrgios is the only Australian other than Lleyton Hewitt to beat 17-time Grand Slam winner Federer since 2001.
He had already emulated Federer by making two Grand Slam quarter-finals as a teenager, the latest after returning from injury at this year's Australian Open.
Of the 'big four' - Federer, Nadal, Novak Djokovic and Andy Murray - only Nadal (French Open twice) had lifted a Grand Slam trophy as a teenager.
"The history books tell us it's pretty rare what Nick's doing, certainly in this day and age there aren't as many teenagers [two in top 100] excelling like Nick has," Draper said.
"The top 100's a lot older, it's going to be a lot more difficult I believe to see the [Michael] Changs, [Boris] Beckers or Hewitts who were dominant early.
"He's shown his form on hard and grass courts, clay hasn't been his strong suit but he's taken down one of the best players in the world on it.
"But he's a bit out of the box, he's tall, got great weapons and skill.
"When you've got as much firepower and belief as Nick does, it doesn't really matter what the surface is."
Draper said a big focus for Kyrgios will be bringing the same mindset consistently.
"When you're an adrenaline junkie like Nick is, maintaining that energy and focus level is difficult," he said.
"With so much hype and excitement around certain matches, you want to relive that all the time.
"But he lives for those moments and that's one of the reasons why he's one of the most exciting players out there. It's a rare quality, and very tough to teach."
Although his win over Nadal was on a far bigger stage, Kyrgios grew up idolising Federer and rated it his career highlight.
Kyrgios is the youngest player in more than a decade to have conquered Nadal and Federer, and first to do so while both were in the top 10.
"This is definitely the greatest win over my career so far," Kyrgios said after saving two match points and clinching victory on his sixth.
"It doesn't really feel real at the moment. I didn't really feel as if I was playing out there - it almost felt like I was watching.
"It was similar to that match at Wimbledon when I played Rafa. It's a strange feeling. It hasn't happened many times in my career. It's happened twice now. It's pretty exciting."
Federer invited Kyrgios to train with him in Zurich before last year's French Open, and admitted he couldn't handle his firepower.
"My problem was I couldn't return his first serve," Federer said, who watched 22 aces whiz by.
"He's got a wonderful serve, good potential, so I hope he keeps working hard and that he can compete for the best spots in tennis," Federer said.
