For the past decade, professional tennis has been dominated by four men: Roger Federer, Rafael Nadal, Andy Murray and Novak Djokovic.
But eventually, that will have to change.
With Federer on the wrong side of 30 and Nadal still battling injuries, soon there will be some young, lesser-known lights joining Murray and Djokovic at the top, and that will start at the 2013 Australian Open.
Many top-flight talents don't even begin to reach their full potential on the court until their late twenties, but success has come early for a handful of top-30 threats, and here's a look at some of the young stars that will make surprising runs through the draw in Melbourne.
As the No. 20 seed, Las Vegas native Sam Querrey isn't expected to make too much noise at this year's tournament. But after winning his first match, he's set to take on a unranked Brian Baker in the second round.
The 25-year-old has enjoyed success on hard courts, as just two of his seven career titles have come on grass or clay, and he'll be hungry to advance beyond the second round at the Australian Open for the first time since 2008.
Querrey had success towards the end of the 2012 season, making third round appearances at both Wimbledon and the U.S. Open, and he could go one further this year, setting up a likely fourth round matchup against defending champion Djokovic.
22-year-old Milos Raonic is one of the most intriguing youngsters on the tour, as the Canadian boasts one of the game's most powerful serves. If he can find consistency, he'll be a force to be reckoned with for years to come.
Raonic has enjoyed more success at the Australian Open than any other major. He reached the fourth round in 2011 and the third round in 2012. So if he's going to take the next step in his development and earn a place in the quarters, there's no better time than the present.
Raonic won't face a higher seed until the fourth round, at which point he'd face four-time champion Roger Federer. But there's no telling what the fiery Ontario native can do if his serve's on.
Coming off a fourth round performance in his last Slam appearance at the 2012 U.S. Open, Raonic should duplicate that feat in Melbourne, assuming he keeps his composure on the big stage.
One of the wild cards of the tournament is Ukraine's Alexandr Dolgopolov, who has quickly become one of tennis' most exciting young talents, who enters the Open as the No. 17 seed in the draw.
Like Raonic, Dolgopolov has been at his best in the Land Down Under, as the 24-year-old Ukrainian reached his first career Grand Slam quarterfinal in Melbourne in 2011, and advanced to the fourth round a year ago.
In 2011, Dolgopolov actually took Andy Murray to four sets in their quarterfinal clash, announcing that he is not to be taken lightly by even the tour's most decorated stars.
With a deceptively strong forehand and a dangerous slice, Dolgopolov has the tools to make a deep run in Melbourne, as his game is best suited for hard surfaces.