Sloane Stephens of the United States reacts after a point against Mandy Minella of Luxembourg during their first round women's singles match on Day One of the 2013 US Open at USTA Billie Jean King National Tennis Center on August 26, 2013 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Elsa/Getty Images)

Who is Sloane Stephens?

Sloane Stephens is one of the top tennis players in the world and she’s hasn’t even turned 21 yet. Her 2013 began with a bang, upsetting American tennis legend Serena Williams in the quarterfinal at the Australian Open.

Many in the sport saw the victory as the changing of the guard, but Stephens still has plenty of work to do before the comparison is even possible. She’s reached at least the fourth round in her last five Grand Slam tournaments and it’s only a matter of time before she gets her first major victory.

Why is she on theGrio’s 100?

Stephens is a powerhouse of potential in women’s tennis. She recently hired Paul Annacone, former coach for all-time greats Pete Samprass and Roger Federer.

Tennis.com’s Steve Tignor breaks down Stephen’s game:

“She’s fast, she’s strong, she has easy power, she can pop a big serve when needed, and most important of all, she can put the ball past her opponents from the baseline. After spending the off-season with Paul Annacone, she should be heading for the Top 10.”

The key for Stephens is consistency. She’s been criticized for her lackluster play at some of the WTA’s smaller tournaments but has been able to rise to the occasion, most notably in Grand Slams. She has a dynamic personality that’s great for the game and American tennis.

After all, if you’re the second-best American player after Serena, that’s pretty darn good.

What’s next for Stephens?

Stephens advanced to the fourth round of this year’s Australian Open before falling to Victoria Azarenka. Stephens has shown strides in her game since her breakout 2013 campaign. She’ll turn 21 in March and has an excellent chance to finally get over the hump for a major victory.

On Twitter, Stephens laid out her plan for 2014:

Follow Sloane Stephens on Twitter @SloaneTweets