Top seed Andy Roddick continued his fine form on return from injury as he moved into the semifinals of the Legg Mason Classic by beating fellow big-server Ivo Karlovic in Washington on Friday night. The American, who notched his 500th career win in the previous round, triumphed 7-6 (7-4) 7-6 (7-5) against the 11th-seeded Croatian to set up a last-four clash with compatriot John Isner
