Scherzer improved to 13-0 and one more win will make him the first pitcher since Roger Clemens in 1986 to open a campaign with a 14-0 mark.
He allowed two runs on seven hits over 6 1/3 innings. Scherzer struck out eight and has fanned at least six in all of his 17 starts this season.
Alex Avila hit a three-run homer for the Tigers, winners of two in a row after losing six of seven.
Toronto lost for the seventh time in 10 games. All six runs were charged to Josh Johnson, but only one was earned. He gave up seven hits in five innings.