Serena Williams takes an 18-match winning streak at the US Open into her quarterfinal meeting with Flavia Pennetta at the Grand Slam event tonight

Two-time defending champ Serena Williams takes an 18-match winning streak at the US Open into her quarterfinal meeting with Flavia Pennetta at the Grand Slam event tonight. The top-seeded Williams is 5-0 lifetime against Pennetta losing just one set to the Italian.