A mismatch loomed in Arthur Ashe Stadium tonight when the world No. 1 and best server in WTA history squared off against the second-youngest and shortest of the US Open quarterfinalists.  Serena Williams has shown little mercy to her first four opponents, losing no more than five games in any of those matches.  In the view of many observers, her revenge on Sloane Stephens for an Australian Open loss posed a greater hurdle than her quarterfinal opponent could.

Carla Suarez Navarro had won just two games from Williams when they met this spring on the clay of Rome, historically Suarez Navarro’s best surface and Serena’s worst.  She also had won just three games in their only previous hard-court meeting.  First things first, then.  Before she could entertain hopes of making this match truly competitive, Suarez Navarro needed to jump on the scoreboard quickly to forestall the potential embarrassment.

That would be easier said than done against a server like Serena, who can exploit her small opponent’s height by stretching her off the court with wide serves.  She cracked two of those wide serves for aces in the first game en route to a love hold.  Suarez Navarro defended impressively when she did find her way into the rally, forcing Serena to hit several quasi-winners to end the point.  But the world No. 1 showed discipline and crisp footwork in meeting that task. 

As it had earlier in the afternoon, the wind rippled through the stadium to make serving a greater adventure.  Serena does not toss her ball particularly high, though, so those conditions did not affect her as much as they might have a taller woman.  Through three service games, her only point lost came on a double fault.  A player box that included six-time major champion Boris Becker could have found nothing to nitpick in that area of her game.

Perhaps the cavernous spaces of Arthur Ashe flustered Suarez Navarro, who had spent her tournament on outer courts.  She double-faulted to fall behind by a double break, and that mission of asserting herself on the scoreboard early turned into a mission of asserting herself on the scoreboard at all.

The 22-minute first set ended as the second bagel of 2013 that Serena had served Suarez Navarro.  Never holding a game point or break point during that set, the underdog knew that her 25th birthday could not get much worse. 

It did not get much better in the immediate future as Suarez Navarro double-faulted on break point for the second time.  That mistake ended a game in which she had appeared to gain a foothold as she found better depth on her groundstrokes.  With the match essentially over at that stage, Serena’s main task consisted of staying focused.  Serving at 4-0 15-15, seven points from a double bagel, she fluffed two easy forehand putaways in the forecourt.  Suddenly, Serena found herself in danger of dropping serve for no reason other than her own carelessness.

Deft play at the net erased another break point, and the defending champion locked back into her groove to deny Suarez Navarro the best chance that she would have.  Serena had fallen one game short of a double bagel in the first round against Francesca Schiavone.  She would not be denied that achievement here.  This quarterfinal marked Serena’s first double bagel in the quarterfinal or later of any tournament.

Two days of preparation for Friday’s semifinal now await the world No. 1.  The sixth-ranked Li Na will offer much sterner resistance for Serena, having played her close on hard courts many times in the past.  Through five rounds, though, nobody can doubt that Serena is the favorite to defend her title.