Trailing 3-1 in entering the sixth, the D-backs sent eight men to the plate.
Jason Kubel's RBI single cut the deficit to one run and chased Brewers starter Randy Wolf. After Jose Veras (3-2) came in to pitch, Taylor Green mishandled Paul Goldschmidt's grounder, sending Kubel to second.
Ryan Roberts' single then tied the game and Blanco followed with another run-scoring hit to put Arizona ahead.
The rally made a winner of Bryan Shaw (1-2), who had induced Nyjer Morgan to ground into a double play in the top of the frame, snuffing out a Brewers uprising.
J.J. Putz racked up his 11th save for Arizona, which took the rubber game of a three-game series.
Green finished with two hits and an RBI for Milwaukee.