Defoe scored in the first half, and Bradley made it 2-0 in the 89th. Kekuta Manneh scored for Vancoouver in stoppage time.
The second leg is next week in Vancouver. In the other semifinal opener, FC Edmonton beat the defending champion Montreal Impact 2-1.
The Voyageurs Cup winner will earn a spot in the 24-team CONCACAF Champions League. The CONCACAF Champions League winner advances to the FIFA Club World Cup.