Bartlett's first-inning triple gave San Diego a 1-0 lead and the Padres never looked back, cruising to their third straight victory over the Astros in wrapping up a four-game series.
Chris Denorfia scored twice and Chase Headley contributed an RBI double for San Diego.
Mat Latos (4-6) earned the win in a five-inning performance, yielding two runs on six hits and two walks. He struck out three.
Rookie Jordan Lyles (0-1) was saddled with his first major-league loss, surrendering four runs on five hits before being pulled after four innings.
Hunter Pence and Carlos Lee drove in runs for the Astros.