Before the US Open began, the majority felt Serena Williams was the favorite to not only win the title but complete her bid for a calendar-year Grand Slam.  Victoria Azarenka and Simona Halep were also popular picks as spoilers, as were Petra Kvitova and Venus Williams to a lesser extent.  Not many would have pegged Flavia Pennetta to reach the final, and even fewer would have predicted her compatriot Roberta Vinci to do the same.  Yet both Italians have defied the odds and will now play each other for the right to be crowned the 2015 US Open women's singles champion.

To say that neither woman expected to be in this position would be a huge understatement.  After defeating Simona Halep in the semifinals, Pennetta candidly admitted that she did not think she would be going far in New York.  Likewise, Vinci stated she did not expect to pull off one of the biggest upsets in the history of sports when she dealt Serena Williams just her third loss of the season to shockingly advance to the final.  Each now has a golden opportunity to claim her maiden major singles title, and it is anyone's guess as to who will react best to the situation to seize it.

When dissecting their games, Pennetta has to be the player favored to win.  She is the taller of the duo and generally gets more mileage out of her serve.  She possesses greater firepower from the ground, and her backhand in particular is much more effective at penetrating through the court.  As Vinci showed in her semifinal with Williams, however, her backhand slice can be tricky to handle.  She can use it to draw an opponent in or as a means to charge the net herself.  Vinci is arguably slightly better in the forecourt than Pennetta as well, but the 26th seed is no slouch up there either.  Vinci will have to make more of a concerted effort to move forward, or else Pennetta will look to do so and negate the lone area where Vinci has an edge on her opponent. 

Of course, it is safe to assume that both women know exactly what they have to do to garner the win.  They have known each other for over a decade and have been Fed Cup teammates frequently during that time span.  They know their games inside and out, so this could easily evolve into a chess match as each woman looks to best employ her strengths while exploiting her opponent's weaknesses.

While the two combatants will be asking each other many questions as they probe for a way to gain the upper hand, the biggest question of all will center around which woman is more ready for this moment.  In her semifinal match against Simona Halep, Pennetta performed like a player who believed she belonged there and expected to advance.  Vinci was equally if not more impressive in her semifinal where she stunned the tennis world and Serena Williams as she ended the American's bid to win the calendar-year Grand Slam.  She played smart, all-court tennis and refused to allow the occasion to get the better of her. 

But as phenomenal as those two efforts were, a major final is a completely different animal.  Over the years, so many players have come out with the proverbial “deer in the headlights” look when contesting their first Grand Slam singles final, and it remains to be seen if either of these two players will follow that trend.  Furthermore, while Pennetta's win over Halep was technically an upset, it was nowhere near the magnitude and significance of her countrywoman's win over Williams.  It is fair to speculate if Vinci will be able to sufficiently come down from the emotional high of that victory to do the same to Pennetta.  Along those lines, it should be interesting to see how Pennetta mentally responds to seeing Vinci on the other side of the net.  Like most, she had to figure she would be the huge underdog facing Williams in the championship match.  Instead, she now finds herself as the seeded favorite.  She leads her head-to-head with Vinci 5-4 and has won their only two meetings at a major, one of which came at this venue in 2013.  She may be grateful for the knowledge that her odds of securing her first major singles title dramatically increased when Vinci upset Williams, but she may also find it a whole lot harder to swing away freely come Saturday.

It is a shame in many ways that Vinci's upset of Williams has left this final feeling anticlimactic.  Neither woman is a household name, and many are sorry that they will not have the chance to see Williams make history.  But both Pennetta and Vinci are deserving champions.  They have played some incredible tennis to reach this stage, and to have done this in the twilight of their careers is even more remarkable.  Pennetta will be the favorite on Saturday, but Vinci cannot be ignored.  As the unseeded Italian so emphatically proved, anything can happen.  But as the higher-ranked player with the more imposing game, Pennetta has to like her chances of earning her first major singles title.