Venable drove in two runs with a second-inning home run and had two of the Padres 10 hits off three Marlins pitchers.
Yonder Alonso and Everth Cabrera drove in a run apiece for the Padres, who won for the 10th time in their last 13 games. Eric Stults earned the win by holding Miami to one run on seven hits over 6 2/3 innings.
Alex Sanabia (2-5) suffered the loss. He lasted 4 1/3 innings, allowing four runs – three earned – on nine hits before being taken out of the game with tightness in his groin.
Marcell Ozuna drove in Miami's only run on a two-out single in the fourth.