The Twins and Indians engaged in a marathon pitchers' duel in a contest that was delayed nearly 2 hours due to rain, but Thome ended it when he blasted his 587th career homer and No. 23 of the year off Justin Germano (0-2) to give first-place Minnesota the victory.
The round-tripper allowed Thome to pass Frank Robinson into sole possession of eighth place on baseball's all-time home run list and boosted the first-place Twins to a six-game lead over the Chicago White Sox in the American League Central.
Matt Guerrier (4-7) got credit for the win after working out of an 11th-inning jam and Matt Capps pitched a perfect 12th for his 12th save as a Twin.m
Minnesota starter Nick Blackburn hurled eight shutout innings, scattering five hits, walking two and fanning three.
The Indians' Carlos Carrasco matched him for 7 1/3 innings, allowing no runs on five hits.