Last year a wrist injury kept Argentina's Juan Martín del Potro from defending his U.S. Open crown. This year the weather held him back: He buckled in the 85° heat against Frenchman Gilles Simon, losing his third-round match in four sets on Sunday. "I'm still trying to recover my game, my fitness, my mind, everything," says the 18th-seeded Del Potro. "I know that's tak[ing] a long time, but I'm doing [it] faster than everybody [is] thinking." ... Australian Open champ Kim Clijsters withdrew before the start with a strained abdominal muscle injury, while the French (Li Na) and Wimbledon (Petra Kvitova) champs lost in the first round. In the 17 previous instances in which different women won the first three Slam events, this is the first time that none reached the second round at the Open.