Rafael Nadal picked up another victory at the U.S. Open on Sunday but battled a stomach injury that might signal problems down the road for the 23 year old. He roundly beat childhood friend Nicolas Almagro in three sets but had to call trainers out to treat his muscle strain in the third set. The Spaniard missed Wimbledon to recover from tendonitis in his knees. Meanwhile, Serena Williams seems on track to bringing home her 12th major as she dominated Daniela Hantuchova in only 64 minutes for her fourth-consecutive straight-sets victory. Her sister, Venus, was not so lucky. She lost to Kim Clijsters, fresh out of retirement, in the fourth round.