Roger Federer

Williams, 40, and Federer, 41, have both announced in short succession their plans to retire, leaving the tennis world without two of its most iconic players.

At age 41, his body is telling him the time has come, the Swiss tennis great said in a video message released on Thursday. Federer has won more than 100 titles, including 20 Grand Slam singles wins.

It's day two of the French Open. NPR's Mary Louise Kelly talks to Sports Illustrated executive editor Jon Wertheim about what to expect from tennis' aging greats and up-and-comers.

The tennis legends will meet at a mixed doubles match in Perth, Australia. They have been on the international tennis circuit for decades and hold 43 Grand Slam titles between them.

The win breaks a tie Federer, 35, held with Pete Sampras for the most wins at the legendary tournament. It adds to his record for most Grand Slam singles championships, which now stands at 19.

Either star could be the oldest Wimbledon winner of the Open era, and Williams could claim oldest Grand Slam title. Williams, 37, faces off with Garbine Muguruza; Federer, 35, plays Marin Cilic.

The matchup answers the prayers of tennis fans eager to see a ninth Grand Slam final between the pair. Neither player won a Grand Slam last year.

For now at least, the Australian Open's final bracket is strictly for the over-30 club, as Roger Federer also earned a spot in the men's final.

The Grand Slam tennis champion announced he needs more time to recover from knee surgery. He plans to put his energy toward coming back strong and healthy in 2017.

He now trails only Martina Navratilova, who won 306 matches at the highest level of tennis. Federer, 34, is currently ranked No. 3 in the world.