The biggest upset so far of the US Open occurred Thursday morning as unseeded Flavia Pennetta, ranked 83rd in the world, dominated No. 4 seed Sara Errani in straight sets, 6-3, 6-1.
Pennetta, who has made it to the quarterfinals three separate times at the US Open, benefitted from seven aces (to Errani's none) and overpowered last year's Open semifinalist. Pennetta scored 33 winners, and the 31-year-old continued to blast the ball, averaging 103 mph on her first serve, 25 mph faster than her opponent.
For Errani, it's the second straight disappointing major as the Italian exited Wimbledon in the first round this past summer.
Pennetta will take on the winner of Russia's Svetlana Kuznetsova (No. 27) or China's Shuai Peng in the third round.