August 29th marks the kickoff to the 2011 US Open, one of the four Grand Slam tournaments. Last year, Rafael Nadal won his first US Open title and Kim Clijsters became the first woman to repeat as Women's Singles champ since Venus Williams in '01. She won't be threepeating as she withdrew from play with stomach muscle injury. Those games of "tummy sticks" can get pretty intense. Anyway, if you're not a diehard tennis fan, you might opt not to watch. Big mistake. You'll be missing out on some of the hottest athletes in the world. Luckily, we've pinpointed the definitive list of ball-bashing babes to keep an eye on in this year's affair. Check it out then let us know if we missed anyone in the comments section after the jump.