Paul Goldschmidt singled in the ninth, seeing his streak of games with a home run at six games.
The Cardinals rallied late to beat the Astros 5-3 on Friday, but Houston won 8-2 Saturday night and 6-2 on Sunday afternoon.
The Astros wrapped up their scoring in the eighth inning. After George Springer doubled and Jose Altuve singled, Michael Brantley doubled to the gap in right-center to make it 6-1.
The Cardinals finally broke through in the sixth inning, getting a two-out double from pinch-hitter Rangel Ravelo at Busch Stadium to drive in a run and cut the Houston lead to 5-1.