The Twins won their fifth straight game and Detroit lost for the eighth time in 11 games. The Tigers have seen their advantage over Minnesota in the American League Central reduced to three games.
Minnesota and Detroit will meet twice more in this series and have four games scheduled against each other at the end of the month.
Duensing (4-1) allowed four hits and walked one before turning things over the bullpen to complete the shutout.
Closer Joe Nathan put runners on second and third with two out in the ninth before getting Aubrey Huff on a liner back to the mound. It was Nathan's 42nd save.
Michael Cuddyer put Minnesota in front with a two-run homer in the fourth. Delmon Young doubled home a run in the sixth.
Copyright 2009 by United Press International.