Giant South African Kevin Anderson insisted he never gave up hope of landing a significant Grand Slam blow despite being just nine months shy of his 30th birthday.
The Johannesburg-born, Florida-based Anderson stunned world number three Andy Murray at the US Open on Tuesday to reach his first Grand Slam quarter-final at the 27th attempt.
His 7-6 (7/5), 6-3, 6-7 (2/7), 7-6 (7/0) win over the 2012 champion, fought out over four hours and 18 minutes, was also his first win over a top-10 player at the Grand Slams in 16 matches.
The stunning victory on Louis Armstrong Stadium ended Murray`s run of 18 consecutive Grand Slam quarter-final appearances.
Anderson, who stands at a towering 6ft 8in (2.03m), only turned pro in 2007 at the age of 21, choosing to complete his University of Illinois studies.
"My body`s holding up great. I really do as much as I can to take care of myself," said Anderson, the first South African since Wayne Ferriera in 1992 to make the quarter-finals in New York.
"Going to college and turning pro a little bit later, I always felt myself a little younger than maybe some of the other guys my age who have been on the tour a little bit longer.
"It takes a bit more out of you than I think it was when I was in college and not traveling as much."
He also believes he can tap into the staying power of the leading 30-plus players on the tour.
Roger Federer and Stan Wawrinka, his last-eight opponent, are comfortably in the top five.
"Just watching Roger playing at 34, just moving incredible. Obviously he`s one of the best athletes of all times," Anderson said.
"Maybe tough to compare myself to him. Ivo Karlovic is over 35. I definitely feel my trajectory is still going up. I`m still improving. My desire is still there. Right now I don`t think age is something to worry about."
"Top 10 has been a lifelong dream for me. I feel like I`m getting closer. Even top five, I think that`s ultimately where I want to be."
Anderson fired 25 aces and 81 winners past Murray to record just his second win over the British player in seven clashes, four years after his first.
Anderson said the memory of his heartbreaking loss to world number one Novak Djokovic at Wimbledon this year after leading two sets to love had clouded his thoughts at one stage Tuesday.
"It was definitely on my mind quite a bit there because I felt we were playing some long points," he said.
"I was fatiguing a little bit in the third. But I just stuck with it. I think it was important for me going into the match, thinking back to Wimbledon, the way I played there.
"That`s how I wanted to play again today. Once I was up two sets to love, I think it was important not to think about it. I was just really happy with the way I stuck the course, especially in the fourth set."
Anderson hopes his win might at least push tennis into the headlines back home in rugby-obsessed South Africa, where the country`s fabled Springboks are preparing for the World Cup.
However, he is aware that not having played Davis Cup since 2011 for South Africa, there might be fears he will defect to the United States team.
Married to an American, he is in the final steps of becoming an American citizen himself.
"I think maybe I`ll be eligible sometime next year, but in terms of Davis Cup, no, I`m not going to be playing for the US."