It is the matchup that fans of American tennis have been salivating over since the draw came out more than a week ago: Serena Williams vs. Sloane Stephens.  It is a clash of compatriots, a case of the next generation challenging the old guard, and unquestionably, it is a grudge match.  Without a shadow of a doubt, it is a compelling encounter that is bound to have tongues wagging.

In some ways, it is amazing that this is such a highly anticipated match, since based on history there is no comparison between the two.  Williams, currently ranked No. 1 in the world, is the most decorated active player on the WTA.  Aside from multiple Olympic Gold Medal performances in both singles and doubles, Williams owns sixteen major singles titles and nearly as many in women’s and mixed doubles to go along with them.  Stephens stands on the opposite end of the spectrum.  She burst onto the scene only just last season.  Stephens has yet to win a tour-level title and has been a downright disappointment at the regular tour events, judging by the form that she can produce at the majors.

This showdown between Williams and Stephens also has earned its “must-see” status in spite of the fact that, at best, theirs can only be described as a budding rivalry.  The two have played just twice before, with both meetings coming earlier this year in January.  Williams won the first in Brisbane, while Stephens won the second at the Australian Open.  It was that second match – and the controversy that followed – that have added the element of intrigue to their fourth-round showdown at the US Open.

It was Stephens’ controversial comments that came a few months after her win over Williams in Melbourne that most will remember.  The younger American very publicly called out the veteran in the May 13 issue of ESPN The Magazine by essentially saying that Williams was unfriendly and behaving like a sore loser.  To Williams’ credit, she took the high road and refused to let the controversy grow.  Stephens has also done her best to move away from that ugly episode, but she has made it clear that she is not sorry for what she said.  You can be certain that this will not be lost on Williams, who is apt to be out to punish Stephens for the public scolding she dished out in May.

The other reason that Stephens’ win at the Australian Open makes the match so compelling is that Williams, perhaps more so than most players, hates to lose.  If you need an example of just how much, look at what she has done to Maria Sharapova.  As a teenager, the Russian notched two victories over Williams in 2004, including a shocking win in the Wimbledon final, which solidified her status as a superstar of the sport.  Williams almost seems to have taken those losses personally and has defeated Sharapova in every match they have played against one another for the last nine years.  Undoubtedly, she will be keen to do the same to Stephens. 

Knowing all of this coming in, it is hard to guess just what to expect when these two face off for the third time this season.  From a physical standpoint, the odds favor Williams.  Stephens has a nice all-around game, but she has a tendency to hang out too far behind the baseline against the bigger hitters, which is something she cannot afford to do against someone like Williams, who is always looking to dictate play.  The other issue facing Stephens is that Williams does everything that she does, and Williams does it better.  This is particularly the case with the Williams serve, which is arguably the greatest in the history of the women’s game.

But Sunday’s match will not just be about the physicality aspect.  The mental aspect will play a part, too, and it is an aspect that could go either way for either player.  For Stephens, she could go in swinging freely.  She is not expected to win, and having yet again booked a spot in the second week of a major, there is no shame if she would bow out now.  On the other hand, she may feel the pressure to put in a repeat performance of what she did in January to back up that Australian Open victory over her veteran compatriot. 

For Williams, this is a match that she is apt to get up for and go in highly focused.  She will be looking to avenge her Melbourne loss to Stephens, and she has the added benefit of knowing that the match is in her hands.  On the flipside, Williams has increasingly shown signs of nerves this year.  Most agree that if Williams only wins one major in 2013, she will consider it a disappointment, which is why she will likely be feeling added pressure to come up big in New York.  At age 31, she also knows the opportunities to be in with a chance of winning a major are going to grow ever rarer.

So who knows what this Round of 16 match will bring.  It could be a classic.  It could be an over-hyped washout.  It could be the passing of the torch.  It might be another lesson for a young star.  Either way, it should be another interesting chapter in this budding rivalry.