London (AFP) - Novak Djokovic insists reaching the elite 800-win club is only the latest milestone in his quest to rewrite the record books, refusing even to rule out playing beyond his 40th birthday.
Djokovic became only the 10th man in the Open era to reach 800 match wins as the former world number one moved into the Queen's Club semi-finals with a 7-5, 6-1 victory over Adrian Mannarino on Friday.
The 31-year-old will play France's Jeremy Chardy -- a 6-4, 6-4 winner over American youngster Frances Tiafoe -- on Saturday as he bids for a second Queen's final appearance.
If Djokovic wins the semi-final and goes onto take the Queen's title for the first time, he will pass Stefan Edberg into ninth place on the all-time wins list.
Jimmy Connors is on top with 1,256 wins ahead of second placed Roger Federer, who has 1,156.
With Federer still going strong at age 36, Djokovic sees no reason why he can't enjoy similar longevity to the Swiss star, even joking that he could play into his 50s.
For now, the 31-year-old would be satisfied with keeping fit enough to have a shot at reaching the 900-win mark which only Connors, Federer, Ivan Lendl, Guillermo Vilas and Rafael Nadal have surpassed.
Asked how long he can play for, Djokovic grinned, saying: "Who said 40? I said 50! So it's 19 years (left in his career). I have plenty of time to make a couple more wins.
"50, 60, 70. I don't know. And I don't want to put any limit or any number to it.
"I will play as long as I feel like playing. So hopefully I can have many more years, because I truly enjoy playing this sport.
"I'm just grateful I'm able to do something that I really love and can be successful in."
- 'Doubtful moments' -
Djokovic is through to only his second semi-final of a troubled campaign as he hunts his first title in 2018.
He is a lowly 22nd in the rankings after an embarrassing French Open quarter-final defeat against Italian journeyman Marco Cecchinato.
Hampered by an elbow injury last year, Djokovic hasn't earned a major title since competing his career Grand Slam by winning the 2016 French Open.
Djokovic is slowly getting back in the groove at the Wimbledon warm-up event.
But the 12-time Grand Slam champion admits there were dark days when he was forced to consider whether he would ever recapture the form that made him the world's best just two years ago.
"There were times when I was thinking and questioning everything when I was injured and going through surgery process, but, you know, everyone has those moments," he said.
"Everyone has doubtful moments. So that's life. Life comes in cycles and teaches you lessons. Whether you're going to learn them or not, it solely depends on you.
"As I said, I don't like to put any numbers on how long and when it's going to end. I would rather say 'hey, I'm playing great, back again'.
"I'm 31 on the paper, but I'm 19 in the real sense. I just love to keep on going and see where it takes me."