Australian teenager Nick Kyrgios set his sights on one day taking Rafael Nadal's world number one ranking after beating the Spaniard at Wimbledon.
Wildcard Kyrgios, 19, won 7-6 (7-5) 5-7 7-6 (7-5) 6-3 on his Centre Court debut and will play Milos Raonic in the quarter-finals on Wednesday.
Former champion John McEnroe said Kyrgios could win the title this year and has high hopes for his future.
"I want to be the number one player in the world," said the Australian.
"That's my motivation. I've never had anything like this happen in my life."
Ranked 144, Kyrgios is the first man outside the top 100 to beat a world number one at a Grand Slam since Jim Courier lost to Andrei Olhovskiy in 1992.
Kyrgios has spent much of this year on the lower Challenger circuit, winning a title in Nottingham on the eve of Wimbledon after losing to world number 185 John Patrick Smith the week before.
"It's just extraordinary," said Kyrgios. "I'd never think after that match I'd be in the quarters of Wimbledon three weeks later."
|Route to the final|
|Bottom half of draw:||If Nick Kyrgios beats Milos Raonic on Wednesday, he will face winner of Roger Federer v Stan Wawrinka in Friday's semi-finals|
|Top half of draw:||Winner of Andy Murray against Grigor Dimitrov will play Novak Djokovic or Marin Cilic in the other semi|
Three-time champion and BBC commentator McEnroe compared Kyrgios to German Boris Becker, who won Wimbledon as a 17-year-old in 1985.
"He absolutely believed that he was going to win this match and he is acting to me like he could win this tournament," McEnroe said.
"The last guy I saw like that was Boris Becker, a young teenager with no fear whatsoever who just believed 'no matter what comes my way, I am going to be better than them'."
Asked about the prospect of winning the title on Sunday, Kyrgios said: "I hope so. I'm going to stay grounded.
"I'm going to go home tonight and do everything possible for my next round tomorrow. Milos has probably got the best serve in the world. I'm just going to go out there and have fun again."
Kyrgios hammered down 37 aces and was broken only once by 14-time Grand Slam champion Nadal.
"On the big stage, it's something I thrive on," said Kyrgios.
"The atmosphere, the crowd. I just love it when at 5-3 in the fourth set, they erupted, the crowd. I just love that feeling.
"At that stage, you just think about all the work you put in. Especially with my serve, if I just go after it, hit the right spots, I'm going to have a pretty good shot to close out a match like that today."
The teenager will return 24 hours later to take on Raonic, the equally big-serving eighth seed, in the third match on Court One.
"It's going to be a tough ask, but I'm going to do everything possible and see how my body responds tomorrow," said Kyrgios.
"If I come up short, I come up short. I'm going to give it my best shot and, whatever happens, happens."
Andrew Bulley coached Kyrgios between the ages of four and 14 and did not expect the teenager to become a world beater.
"I never thought it," he told BBC 5 Live's Phil Williams show. "You coach these kids and you obviously have hopes and dreams for these children, but there are so many things that can happen along the way,
"In Australia, we've had a lot of players who've been good when they're young and they fade out when they get to the senior ranks.
"Nick, though, seems to have the game to push through and make a mark on the senior tour."
Nadal dropped his own serve just once in four sets against Kyrgios, but admitted he could do little against such strong serving.
"When you have an opponent who decides to hit the ball really strong and serve like that, you are in trouble," said the Spaniard.
"I don't think that I played badly. I hadn't seen him playing on the other surfaces - grass is only two three tournaments a year - but when you serve that big you will always have a chance."
|Who is Nick Kyrgios?|
|Born:||27 April 1995, Canberra, Australia.|
|Parents:||Father, George, is Greek-Australian, while mother Norlaila is Malaysian.|
|2012:||Won junior doubles championships at Wimbledon and Roland Garros.|
|2013:||Won junior Australian Open title.|
|Beat Radek Stepanek in his first Grand Slam match as a wildcard at the French Open.|
|Won Wimbledon junior doubles title.|
|Reached number one in world junior rankings.|
|2014:||Started year ranked 838 in world rankings; will be in the top 100 after Wimbledon, the youngest to break in since Bernard Tomic in 2011.|
|Won three Challenger Tour titles this year, including Nottingham in June.|
|Trained with Roger Federer before the French Open.|
|Donating £5 to Rally for Bally fund for every ace he serves at Wimbledon, in memory of the late Elena Baltacha.|