Houston (2-1) led 6-3 before Smith picked off Matt Schaub's pass and took it into the end zone with 2:39 left in the first half. Less than two minutes later, Doss eluded several tacklers during his first career punt return for a touchdown.
The Baltimore defense did the rest. The Ravens have not allowed a touchdown in eight quarters since their season-opening 49-27 defeat in Denver.
Schaub went 25 for 35 for 194 yards and an interception.
Copyright 2013 by The Associated Press