The Williams sisters and Roger Federer are proof that being on the wrong side of 30 is no barrier to success on the tennis court, but they have had to adjust to stay on top.
More than 40 players at this year's Australian Open are over 30, with Japan's remarkable Kimiko Date-Krumm the oldest at 44, playing her first Grand Slam in 1989.
Others still going strong include Francesa Schiavone, Vera Zvonareva, Daniela Hantuchova and Zheng Jie.
Among the men, world number two Federer at 33 has shown time and again that remaining at the pinnacle in your tennis twilight years is possible.
David Ferrer, Ivo Karlovic, Mikhail Youzhny and Lleyton Hewitt are all into their thirties and still earning a living from the game they love.
Two of the longest-serving members of the tour are the Williams sisters, with Venus making her debut in 1995 and Serena in 1997. Both are still in the fray at ages 34 and 33 respectively.
Serena remains world number one, proving that age really is no barrier.
"When you walk on that court, there is no such thing as age, height, any of that stuff," said Venus after winning her third round match on Saturday.
"It's really an even playing field. It's a matter of can you get the ball in? Can you win the point or not.
"It doesn't matter any of these variables. That's what they are: Variables. I don't think that (age) enters our mind out there."
The stats back this up with 14 WTA titles last year claimed by those in the 30s, led by Serena Williams but also including Venus, Pennetta, Sam Stosur and the now-retired Li Na.
Thirteen of the men's titles won last year were by over 30s.
Perhaps the greatest player of all time, Federer feels he has more success in him despite a shock exit in the Australian Open third round on Friday, insisting: "I don't feel any different to let's say four years ago.
