Conventional wisdom may have it that this US Open is for Serena Williams to win or lose, but there are a select few players who may have what it takes to hoist the trophy here as well, even at the American's expense.  One of those players is Simona Halep.  The young Romanian has skyrocketed to the upper echelons of the sport with her play the last couple of seasons, and she would love to continue her ascent in the sport by winning her maiden major title here in New York.  But she will first have to get by Sabine Lisicki if she hopes to keep that dream alive.

Most would like Halep's chances of advancing in this contest, and not strictly because she is the higher seed.  She has also played some exceptional tennis on the hard courts, winning three titles on that surface that year and her first Premier Mandatory title at Indian Wells.  Add that to her finalist appearances at both Toronto and Cincinnati, and there is no denying that she looks like a tough out on this surface. 

Knowledgeable tennis fans – and Halep if she is wise – will not be quick to dismiss Lisicki's odds in this encounter either, however.  The German's most heroic exploits have come on the lawns of Wimbledon, where she is practically a mainstay in the second week, but she can do damage on the hard courts as well.  She proved that this past spring with her semifinal showing at Indian Wells and quarterfinal finish in Miami.  There is no reason she cannot match her accomplishments at Wimbledon with a good run at Flushing Meadows.

Lisicki definitely has the weapons to get by Halep and into the last eight.  She owns one of the biggest serves in the women's game and possesses more pop on her groundstrokes.  There is a little more variety in the German's game too.  Additionally, Lisicki has better feel in the forecourt, and she looks to move forward with greater frequency than the second seed.  Lisicki plays second fiddle to Halep in the movement department,t though, and Halep's retrieving ability will severely test the 24th seed's ability to play first-strike tennis at a consistently high level over the course of the match.  Furthermore, Halep is superior on the return and is more adept at moving the ball around the court.  Provided she does not make the mistake of going into defensive mode, she should have ample opportunity to control her share of the rallies and keep Lisicki off balance, thereby cutting into the German's advantage in the power department.

Halep already knows what she needs to do to win, as evidenced by her 3-1 record against Lisicki.  And while she has never been beyond the fourth round of this tournament, she has gone deep at the other majors, including a runner-up finish at Roland Garros last season.  Her play at other hard-court events this season certainly suggests she is capable of making a deep run at the US Open.  Then again, Lisicki is very much capable of doing the same.  Like the Romanian, she is a former Grand Slam finalist thanks to her stellar play at Wimbledon in 2012, and logically she knows there is no reason why her game should not translate well to these fast hard courts.  And although she has only defeated Halep once, Lisicki pushed her to three sets in two of her three losses.  Finally, having already secured victories over players like Williams and Maria Sharapova, it seems unlikely that Lisicki will shy away from the prospect of earning a win over Halep.

All in all, this should be a tight match filled with exciting, all-court tennis.  Much will depend on Lisicki, who can be up and down, but if she brings her A-game, Halep will need to respond in kind to avoid the upset.  Expect the Romanian to do that and advance to her first US Open quarterfinal, but do not expect Lisicki to make it easy for her.

There is a lot to be happy about if you are John Isner.  After underperforming at the Australian Open and Roland Garros, and suffering a heartbreaking third-round loss at Wimbledon, the American has gotten over the hump to once again find himself in the second week of a major.  In doing so, he has been able to continue the fine form he has shown all summer and set himself up nicely for the upcoming autumn season.  The bad news for John Isner is that his next opponent goes by the name of Roger Federer.

It is not that Isner does not command respect.  He has been the top-ranked American for portions of his career and has 10 titles to his name.  He has also garnered some impressive victories, reached the quarterfinals of this tournament four years ago, and has a reputation as one of those dangerous floaters that no one wants to face. 

However, Federer presents a formidable challenge to Isner because he holds the edge against the 13th seed in so many departments.  The Swiss is swifter of foot, has more consistency off the ground, boasts more versatility from both the baseline and up at net, and exhibits better returning skills.  Those are a lot of disadvantages for Isner to overcome, which is why if he wants to get by the second seed, two things need to happen.  The first is that the American must have an extraordinary serving day.  He is not going to win a lot of the extended rallies with Federer, so the shorter he can keep the points, the better.  In addition to that, a good serving day could get him to a tiebreak, where it becomes a little more of a crap shoot and slightly increases his odds of garnering the upset.  Secondly, Isner is going to have to take a few more risks on the return and hope that they pay off.  If he is unable to make inroads on Federer's serve, that will increase the pressure he exerts on his own serve.  Short of these two keys, Isner will have to hope that Federer simply has a bad day at the office.

Federer does not look like a man who is about to log a sub-par performance, however.  He backed up his run to the Wimbledon final with some superb play in Cincinnati to waltz to that title, and he has barely broken a sweat through his first three rounds here.  He has significantly more experience playing matches of this magnitude, and although he will not make the mistake of looking beyond Isner, with his dominant 4-1 record against the American, he has to be feeling optimistic about his odds for success on Monday. 

That is not to say that Isner does not have a few areas where he can mine a couple of nuggets of hope, though.  His lone win over Federer came in Davis Cup, so he is equipped with the knowledge that he can beat the Swiss in a best-of-five match.  More importantly, he has had a great summer coming into the US Open.  He won his third consecutive title in Atlanta, reached the final of Washington DC, and made the quarterfinals in Montréal.  He has been able to move through his first few rounds here with relative ease as well, so if ever there were a time where he would be feeling mentally and physically up to the task of dealing Federer a defeat, it would be now.

There will be plenty of folks in the crowd cheering for Isner as the home player to do something special to get by the Swiss and reach his second US Open quarterfinal.  It just is not all that likely to happen.  Federer is holding the majority of the cards in this encounter, and he has looked like the man to beat all tournament long.  There is no reason to expect that to change on Monday.