Sam Querrey returns a serve against Marinko Matosevic, of Australia, during the U.S. National Indoor Tennis Championships, Thursday, Feb. 21, 2013, in Memphis, Tenn. (AP Photo/The Commercial Appeal, ... more 

Sam Querrey returns a serve against Marinko Matosevic, of Australia, during the U.S. National Indoor Tennis Championships, Thursday, Feb. 21, 2013, in Memphis, Tenn. (AP Photo/The Commercial Appeal, Nikki Boertman) less