In sports, fate can be cruel or kind.  For a player trying to come back from an injury, or many injuries, it can seem particularly cruel, pitting him against seeded players early in a tournament and making it difficult to make a deep run and quickly begin rebuilding his career.  Then again, the seeded player is often equally unhappy about the scenario, since he knows that the former top-10 talent is capable of playing well above his current ranking.  That is the situation in which Stan Wawrinka and Juan Martin del Potro now find themselves.  A few years ago, they would have potentially been vying for the title, but on Thursday, they will be fighting for the right to move on to the third round.

Naturally, Wawrinka will be the one favored to get through this match.  He is seeded fourth, and not only has he been playing better tennis, but also he has had the opportunity to actually play tennis.  He is match tough and for the last couple of years has carved out a nice niche for himself toward the top of the rankings.  He has proven himself able to defeat the sport's greatest stars and has accumulated two major titles, including last year at Roland Garros.  He has won two tournaments thus far this season, and although he struggled in the grass-court warm-up events, he still ought to be feeling confident following his semifinal finish in Paris.

Del Potro can only dream of those kinds of results right now.  The Argentine, once ranked as high as No. 4, now resides at No. 165 following several frustrations with various injuries.  He was forced to miss the year's first two majors, but he did reach the semifinals in Delray Beach, and more importantly, he made it to the final four on the grass of Stuttgart before arriving in London.  It is important to remember that del Potro is also a former U. S. Open champion, and prior to all of his injuries, he looked like the man most likely to disrupt the dominance of the Big Four.  He has been prevented from fulfilling that promise, but there is no telling when he might tap back into that prime form and once again ascend the rankings.

Del Potro has a decent shot at rebuilding his legacy by garnering a win over Wawrinka.  He can match Wawrinka in the power department from the forehand wing, and his height gives him an edge on serve.  He also enjoys greater reach, which should allow him to get his racquet on more balls.  Where Wawrinka will hold the edge is his backhand, and that is the shot that could be the difference-maker in this contest.  Wawrinka's one-hander is a thing of beauty, and since Del Potro's backhand is still a little shaky following so many wrist issues, it has become more of a disadvantage.  The Swiss' is more versatile as well, and his slice is bound to be more effective against the lanky Del Potro than vice versa. 

What makes this encounter so interesting, however, is that there is no telling which Wawrinka will show up.  His game may be more finely honed than the Argentine's, but by his own admission, he can be erratic.  And when the wheels come off, the fourth seed has trouble righting the ship.  Del Potro also enters this match holding a 3-2 edge in their rivalry, with all three victories coming in their last three meetings.  Del Potro reached the final four here on his last trip to Wimbledon as well, so if Wawrinka starts to spray the ball, giving del Potro an opening, the Argentine will surely have the wherewithal to take advantage.

All told, this has the potential to be a real treat in the second round.  Del Potro certainly has the game to earn the upset, but it remains to be seen if he is ready to step up to the challenge.  As a result, this match rests on the racquet of Wawrinka.  If he plays as he did in Paris, he gets through to the third round.  If he is not feeling the ball well, del Potro may just send him packing.

Success in sports can only be achieved by overcoming challenges.  Those challenges come in a variety of forms.  Serena Williams is faced with the challenges of having to overcome a fellow American, looking to defend her Wimbledon crown, and trying to tie Steffi Graf's record of 22 major singles titles.  Her opponent, Christina McHale, also faces the challenge of defeating a compatriot.  She is tasked with finding a way to break through at a major, and to do so, she knows she needs to manufacture an upset of one of the most decorated legends in the game.  On Thursday, they will square off to see which woman is able to overcome her respective obstacles to advance to the third round.

No question, the odds heavily favor Williams.  The elder American may be having a slightly disappointing season based on her lofty standards, with Rome the only title she has bagged thus far, but she has been right on the cusp of others, including the Australian Open and Roland Garros.  She is firmly entrenched at the top of the rankings, and with all that she has accomplished in her career, she is a clear favorite every time she takes to the court.

Christina McHale grew up idolizing Serena and her sister Venus Williams, and after seeing what they have done over the course of their careers, she will be keenly aware of the tall task that lies before her.  Four years ago, the American was knocking on the door of the top 20 and looked to be one of the likely successors to the Williams sisters, but prolonged illness and niggling injuries have put a dent in those plans.  She has finally gotten healthy the last several months, though, and has steadily begun to rebuild her game.  McHale won the ITF event in Maui and had a solid clay swing.  She also fought her way through the qualifying to a round of 16 finish in Birmingham prior to arriving at Wimbledon, so she ought to be feeling comfortable on the grass and have a fighter's chance in Thursday's encounter.

Feeling comfortable is just part of the equation, however.  McHale also needs to have the belief that she can upset the top seed, and she does have reason to have at least a glimmer of hope.  The two have only met twice, both meetings coming this year, and Williams won on both occasions.  That said, their match in Miami was a competitive three-set affair, and their match in Rome featured a first-set tiebreak.  The younger American also has the advantage of being the underdog.  It is true that she cannot compete with the experience Williams has accumulated over the course of her illustrious career, but Williams is also forced to cope with the pressure of trying to tie Graf's record.  After falling in the latter rounds of the last three majors, there is increasing talk of whether that pressure is getting to Williams.  She will never admit one way or the other, but there is a case to be made that it is affecting her game.

Of course, more often than not, Williams has found a way to hit through her nerves and snatch a victory.  That is because she is the best player in the sport right now, and that will assuredly be the case against McHale.  McHale can possibly hang with Williams in the forehand exchanges and maybe even get the top seed on the run, but in every other facet, Williams has a distinct advantage.  Her serve is the greatest in the history of the women's game, her backhand is head and shoulders above McHale's, and there is no doubt that she plays better defense and is superior at turning it into offense.  McHale is going to need to have an excellent serving day and consistently execute while playing outside her comfort zone if she is to take Williams out of hers and garner the upset.

Suffice it to say, all signs point to a Williams victory.  McHale could make it interesting.  She may even pull off the unthinkable.  After all, historically, to defeat Williams at a major has typically been easier to do earlier rather than later.  But McHale is going to need to do something extra special or get help from Williams.  Neither scenario looks likely, so expect Williams to move one step closer to defending her title.