Why Garbine Muguruza Will Be Serena Williams' Biggest Challenger in 2016

Serena Williams stands alone at the top of women’s tennis, her monarchy unchallenged by a true rival.

That may soon change if Garbine Muguruza continues her rapid ascent.

While players like Maria Sharapova and Petra Kvitova have won their share of Grand Slams, they’ve never really become reliable threats against Williams. The world No. 1 is a combined 23-3 against those women, including a lopsided 18-2 in her head-to-head with Sharapova. It’s tough to call either of them rivals when their matchups are so one-sided.

As Williams, 34, enters the last few years of her career, someone will eventually take over her mantle. We’ve waited (and waited) for contenders to emerge, but the trio of Simona Halep, Caroline Wozniacki and Ana Ivanovic all lack the requisite firepower and aggression.

Enter Muguruza.

The 22-year-old Spaniard is tall, muscular and athletic, using every part of her frame to impale the ball and keep opponents on the defensive. Her heavy ground strokes are imposing enough, but her results this year are more noteworthy.

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Muguruza burst onto the scene at the 2014 French Open where, appropriately enough, she ousted Williams in the second round. That titanic upset gave fans a glimmer of her potential, which she’s increasingly made good on this season.

Like any young player, Muguruza still hasn’t totally mastered the concept of consistency. Yet her peaks have been darn impressive. At Wimbledon, she not only made the first Grand Slam semifinal of her career, but also her maiden final. By storming past accomplished foes Angelique Kerber, Wozniacki, Timea Bacsinszky and Agnieszka Radwanska, she booked a showdown with Williams for the championship.

Just by reaching that point, Muguruza became the first Spanish woman to make a Grand Slam final in 15 years. Against an in-form Williams, expectations weren't especially high. To her credit, Muguruza came out firing and raced to a 4-2 lead. She'd eventually vanquish that high-quality set and quickly fell behind 5-1 in the second, but Muguruza didn't quit and won the next three games before Williams closed it out.

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Impressed with her opponent's game, Williams effused praise in the post-match interview, saying Muguruza would win Wimbledon soon. As quoted by Wimbledon.com's Ron Atkin, Muguruza responded by saying:

"

It’s good when you hear something like this from a legend. Hopefully I can do it. I was close. 

I enjoyed it a lot. I don’t have words to say how I feel. I love to play this sport, and a Grand Slam final is a dream come true.

I am going to leave here really motivated. This will give me the power to keep practising and improving, to see what else I can do.

"

With that victory, Williams moved to 3-1 against Muguruza. But it's clear this rivalry will be one to watch in the coming years. Both players are baseline warriors, two of the biggest hitters on the WTA Tour. And for the most part, their matches have been extremely competitive. As Muguruza keeps maturing, she may be able to start winning even more against Williams.

Her recent results suggest a turning point is near. 

After a disappointing U.S. Open Series run, Muguruza turned it up several notches in China. At Wuhan, she toppled Sloane Stephens, Ivanovic, Anna Karolina Schmiedlova and Kerber in succession to make the final. An untimely ankle injury forced Muguruza to retire and cede the title, but she wouldn't let that loss set her back.

The next week, Muguruza came back strong in Beijing and found herself in yet another final. There would be no stopping her this time, and she surged ahead of Bacsinszky for the second (and most prestigious) title of her budding career.

Mark Schiefelbein/Associated Press

During that Beijing triumph, Muguruza achieved several important milestones. Besides qualifying for her first trip to the WTA Finals, she also reached a career-high ranking of No. 4 in the world. And she's currently only a single point away from passing Sharapova for the third spot.

So far, her new coaching partnership with Sam Sumyk has worked out extremely well. Sumyk, who once guided Victoria Azarenka to the top, has similar plans in mind for Muguruza. A huge chance soon awaits them.

Because Williams prematurely ended her season, she won't be competing at the WTA Finals. That decision opens a huge door for someone to steal the crown in Singapore. Based on the state of the other qualifiers, Muguruza looks like the one best positioned to go all the way.

As she winds down a successful year, Muguruza will also have her eyes on 2016. Clearly, she's getting closer and closer to winning a major. Easier said than done, but it wouldn't be shocking to see her claim one of those titles next season. She already has the game and swagger of a champion.

Williams enters every tournament she plays as the prohibitive favorite, but Muguruza is poised to steal some of her thunder.

All statistics are courtesy of WTATennis.com unless otherwise noted. 

Joe Kennard is a featured columnist for Bleacher Report. 

Follow @JoeKennard.