Pinch-hitter Jean Segura, however, kept the game alive with an infield single and Logan Schafer drew a walk to load the bases.
Bianchi then struck a soft liner that Cubs shortstop Starlin Castro dove for. He appeared to have a play on it, but ball popped out of his glove and into left field for a two-run single.
Burke Badenhop (2-3) logged the win despite allowing two runs and Jim Henderson collected his 14th save as Milwaukee swept a doubleheader and recorded a third straight win over Chicago.
Dioner Navarro went 3-for-4 for the Cubs.