Mance handed to Tony McQuay who ran a spectacular 43.4 split to take the lead.
David Verburg passed first to silver medalist Tony McQuay who broke first and stayed out of traffic.
In lane 4, Tony McQuay asserted himself against the rest of the field, the first to pass James and run home for the silver.
Tony McQuay ran the turn hard to get the jump on Botswana's fifth place open sprinter, 18 year old Karabo Sibanda at the break.
American Tony McQuay sped around the turn before the break and got enough of a lead to shut the door on the other teams, gaining a couple of metres as they dropped back to regroup and try to pass.