Roddick Rocks Voltchkov as US Leads Belarus 2-0 Andy Roddick and Mardy  quot;Silver quot; Fish put the US up 2-0 Friday in their Davis Cup semifinal match-up against Belarus. Roddick overwhelmed Vladimir  quot;The Vladiator quot; Voltchkov 6-1, 6-4, 6-4, followed by Fish defeating 