Saunders (1-1), making his second start for Baltimore since being acquired from Arizona in an Aug. 26 trade, ended up giving up three hits while walking two and striking out two.
Luis Ayala, Pedro Strop and Jim Johnson combined for 2 2/3 hitless innings to complete the shutout for the Orioles, who pulled to within one game of the first-place New York Yankees in the American League East.
J.J. Hardy drove in a pair of runs while Nick Markakis and Nate McLouth also provided RBI in the victory.
Toronto starter J.A. Happ (3-2) was touched for three runs (two earned) on six hits over six innings as the Blue Jays dropped the first of a three-game series.