A rain-soaked US Open 2009 held a few big surprises for tennis fans. Serena Williams' bizarre, expletive-laden ejection after a terrible call gave the semifinal to Kim Clijsters, although Clijsters appeared headed for victory anyway. Clijsters became the first unseeded woman to win the US Open, coming out of a two-year retirement. She's also the first mom to win since 1980. Juan Martin Del Potro needed no help from officials to upset Roger Federer in the men's final, ending Federer's streak of five US Open championships. Del Potro was appearing in his first majors final, while Federer has played in 16 of the last 17 Grand Slam finals. ( 26 photos total