Led by starting quarterback Trevor Harris, the Saskatchewan Roughriders exploded out of the gate with a touchdown that set the tone for Friday’s 28-16 CFL pre-season victory over the host Winnipeg Blue Bombers. Saskatchewan finished pre-season play with a 2-0 record for the first time since the championship season of 2007. Saskatchewan opened the scoring at 7:46 of the first quarter when Harris hit Derel Walker for a five-yard touchdown pass. The major capped an opening possession in which the Roughriders moved 83 yards over nine plays. Harris went 4-for-4 for 72 yards on that drive — his only one…