Serena Williams Keeps Things Light, Advances to US Open Semis

— -- NEW YORK -- At one time, this would have been an automatic for Serena Williams. Especially at this stage and definitely on this stage, Serena advancing past a Grand Slam quarterfinal was easier to predict than what she would wear next on court.

But down 3-love to 11th-seeded Flavia Pennetta on Wednesday, even Williams wasn't sure what would happen.