The odds suggest that Serena Williams and Caroline Wozniacki will clash for the third time this summer in the US Open final, but a pair of plucky underdogs should not be discounted in Friday’s semifinals.

Serena Williams versus Ekaterina Makarova

The US Open is rapidly drawing to a conclusion, and for Serena Williams, the finish line is looming large.  She is just two wins away from grabbing her 18th major singles title.  But while most people are in agreement that it is difficult to see anyone stopping Williams from achieving that milestone, Ekaterina Makarova, will be keen to prove otherwise.

The Russian definitely has the ability to stay with Williams, but she may need to redline her game if she hopes to get the victory.  Makarova hits both big enough and consistently enough to hang in rallies with Williams and even control them if she is able to get on the offensive first.  She is also more adept in the forecourt, although she will need to be selective as to when she chooses to venture to the net.  Williams has hit solid passing shots this tournament, and with the amount of power she uses off both wings, Makarova may be doing well just to avoid being pinned too far behind the baseline.  That will especially be the case in the American’s service games, for Williams possesses the best serve in the history of the sport, making it very difficult to gain a foothold on the return.

For all of the various tools each woman brings into this match, however, the magnitude of the occasion could inhibit their abilities to utilize them as well as they would like.  Williams has traditionally been all but a sure bet at this stage of a major, particularly at the US Open.  She has also won three of her four meetings against Makarova, with two of the three meetings including bagel sets.  But the American got off to a slow start in her previous match against Flavia Pennetta, and she has also struggled a bit with closing out matches.  The pressure of not only being the heavy favorite in what remains of the decimated women’s field, but playing for her 18th major singles title could hamper her efforts to play at her best.

If Williams is off, Makarova is potentially capable of causing the upset.  She did exactly that two years ago at the Australian Open, when she defeated the American for the first and only time in two routine sets.  It might also help that Makarova has already had the opportunity to face Serena this tournament, since Makarova and doubles partner Elena Vesnina eliminated the Williams sisters from the doubles competition.  Furthermore, in addition to her lone victory, Makarova knows she has played some very tight sets with Williams.  That said, the first set is more critical for Makarova than for Williams.  On two occasions, Makarova has lost a tight opening set with the American, only to quickly fade away in the second.  It would go a long way towards bolstering her belief and planting seeds of doubt in the mind of Williams if the Russian is able to secure the first set.

Of course, few expect Makarova to win the first set and certainly not the match, but this has been a strange US Open on the women’s side.  Makarova has shown a lot of heart to get to her first major semifinal.  If she does not allow the stage and the opponent to get to her, than this could be a highly entertaining semifinal that ends in a shocker.  Just do not bet on Williams allowing that to happen.

Caroline Wozniacki versus Peng Shuai

There have been a number of feel-good stories at this year’s edition of the US Open.  One of them is Caroline Wozniacki, a woman whose professional career was floundering and whose heart was very publicly broken earlier this season.  Another is Peng Shuai, a 28-year-old veteran who was brought to tears after advancing to her first major singles semifinal here in New York.  Now they will square off with a place in the final at stake.

All signs point to Wozniacki being the one to advance to the championship match.  She has played brilliantly this tournament.  She surprised everyone when she found the right combination of offense and defense to get the victory over Maria Sharapova and followed that up with an emphatic win over Sara Errani.  There is no reason to suspect that her game will fail her when she faces Peng, against whom she is an impressive 5-1 in her career.

Peng has been defying the odds a lot these past two weeks, though.  She was responsible for dismissing three seeds to get this point, including Agnieszka Radwanska, who, like Wozniacki, is a player who makes an opponent hit the extra ball.  Peng has been very solid off the ground, finding angles from all areas of the court, and as an accomplished doubles player, it is within her game to get to the net and take time away from her opponent.  She cannot afford to press the issue with the Dane, however.  Wozniacki is great with a target, and after staring down the power of Sharapova earlier in this event, Peng’s groundstrokes are unlikely to rattle her.

Wozniacki is also the less likely of the pair to be rattled by the occasion.  As previously noted, Peng has never been to a Grand Slam singles semifinal.  She performed admirably when making her maiden appearance in a singles quarterfinal in the last round, but raw teen Belinda Bencic likely gave her more help than Wozniacki will on Friday.  Wozniacki has played bigger matches than this in her career as well, and she comes in knowing that she has been successful in the past against the Chinese woman.  In addition to that, most eyes are on Serena Williams, with many feeling that everyone else is merely playing for second place.  That should take some of the pressure off Wozniacki in this semifinal match, even if she is the clear favorite.

Clear favorite or not, Wozniacki will not approach this match lightly.  Peng is playing some of the best singles tennis of her career, and no doubt after already knocking off three seeds, she is more than capable of defeating a fourth.  But Wozniacki has put in the hard yards this fortnight, too, surprising many with her own run in the Big Apple.  No matter how this match unfolds, this US Open represents an inspiring effort by both women.  Only can advance, however, and it will be the bigger disappointment for Wozniacki if she fails to do  so as the one favored to get through for a spot in her second US Open final.