Meanwhile, right-handed starter Tyler Mahle and right-handed reliever Michael Lorenzen combined to hold the Padres scoreless for 8 2/3 innings. Mahle (4-6) gave up five hits and two walks with five strikeouts in five innings.
Lorenzen retired the first 11 Padres he faced before Hunter Renfroe's two-out double in the ninth.
Meanwhile, the Reds jumped on Lockett for four runs on four hits and five walks against two strikeouts in 3 2/3 innings to snap the Padres' three-game winning streak.
Billy Hamilton ran the Reds to a 1-0 lead in the third. He drew a walk, stole second, moved to third on an infield out and scored on Barnhart's grounder to first.
Eugenio Suarez walked to open the fourth and advanced to second on Scott Schebler's single. Both scored on Peraza's double. Peraza then scored on Barnhart's two-out single to make it 4-0.
Gennett homered off Padres reliever Robbie Erlin to open the fifth and widen the lead to 5-0.
The Reds' final two runs came against Bryan Mitchell.
Gennett walked to open the seventh and moved to second on a single by Suarez. Peraza drove in Gennett with a single to right and Suarez scored on right fielder Renfroe's throwing error.
Lorenzen got a rare four-inning save, although the Padres scored twice with two out in the ninth. Raffy Lopez drew a walk after Renfroe's double, and both scored on a triple to center by Freddy Galvis -- a drive that ricocheted off Hamilton's glove as the center fielder was hitting the soft wall. Hamilton was dazed, but finished the game.
--Field Level Media