Center fielder Manuel Margot hit a go-ahead, two-run homer in the eighth inning and right fielder Hunter Renfroe had a homer among his three extra-base hits and scored four runs to help the Padres win 8-5.
Rookie left fielder Josh Naylor reached base three times and scored once, and Wil Myers had a pinch-hit homer in the eighth.
''There were a lot of guys did a lot of good things in the outfield today. It was huge for us,'' manager Andy Green said. ''It's going to be a tough decision tomorrow. I don't have four spots out there. We have three. But all those guys did a great job. I'm really happy for Manny Margot.''
Margot's 10th homer came an inning after Yonder Alonso hit a tying, two-run, pinch-homer for the Rockies, who have lost five straight and 19 of their last 25 to drop a season-worst 13 games under .500.
Renfroe drew a leadoff walk in the eighth off Jairo Diaz (4-3) and Margot then homered to left. Myers homered with two outs off Jake McGee, his 14th.
''It was really exciting because you're able to give the team the lift that it needs,'' Margot said through a translator.
All four outfielders have played well since the Padres traded Franmil Reyes and his 27 home runs to the Cleveland Indians on July 31 as part of a three-way deal that sent Trevor Bauer to Cincinnati.
''We believe in all of them, and have and that's why we felt comfortable doing that,'' Green said. ''Even as much as we love the guy who walked out the door that day, we believe in that group as a whole. Wil is starting to come back to life and it made a lot of sense for us. We know for us to be as good as we can be, we have to have a lefty in that mix. We trust Josh's bat a lot.''
Naylor batted second Saturday night.
''It's a big deal for us to have a little bit more balance in the lineup and not just be running eight righties out there sometimes,'' Green said.
Rookie Fernando Tatis Jr. hit a triple to extend his hitting streak to a career-best 14 games for the Padres, who have won the first three games of this four-game series and four of five overall.
Andres Munoz (1-1) pitched the eighth for the win and All-Star Kirby Yates worked the ninth for his 33rd save.
Renfroe hit a tying home run in the fourth inning and an RBI double in the three-run fifth.
San Diego's Manny Machado, Alonso's brother-in-law, hit an RBI double to snap an 0-for-19 slump.
Padres rookie right-hander Chris Paddack left after six with a 5-3 lead. Craig Stammen started the seventh and promptly allowed Chris Iannetta's double to right followed by Alonso's homer that just cleared the wall in right as Hunter Renfroe leaped for it.
It was the second pinch-hit homer of Alonso's career, his ninth overall this season and his second with the Rockies. He was released by the Chicago White Sox on July 3 and signed to a minor league contract by the Rockies on July 10. His contract was selected from Triple-A Albuquerque on July 23.
''It was a tough at-bat,'' Alonso said. ''Got in there with two strikes and he was able to hang a curveball and I was able to put a good swing on it. That's what you have to do as a bench player. You've got to understand the situation. You've got to be ready at all times.''
Nolan Arenado gave the Rockies a 2-1 lead with his 26th homer, a 399-foot shot off Paddack into the balcony on the third level of the Western Metal Supply Co. Building in the left-field corner with one out in the fifth.
Renfroe tied it leading off the bottom of the inning with a moonshot homer into the stands in left, his 31st.
''Couldn't keep it,'' Rockies manager Bud Black said. ''We'd get a run, they got a run. We get a run, they get a run. It's a little frustrating. Our starting pitching has not been able to really go back out there and put a zero up after we score.''
The Padres added three runs on four hits off Chi Chi Gonzalez in the fifth to take a 5-2 lead. Naylor and Machado hit consecutive one-out doubles. With two outs, Renfroe hit an RBI double and scored on Margot's single.
The Rockies got one back in the sixth when Trevor Story hit a one-out double and scored on Arenado's two-out single. They loaded the bases but couldn't add on.
Padres: Announced LHP Jose Castillo will miss the rest of the season after injuring the middle finger on his pitching hand Thursday night. Castillo was activated from the 60-day injured list earlier Thursday and lasted just four batters before getting hurt.
Rockies: RHP German Marquez (10-5, 4.82) is scheduled to start the series finale Sunday. He's 2-0 with a 7.15 ERA in two starts against San Diego this season.
Padres: RHP Dinelson Lamet (1-2, 3.90) is scheduled to start on four days rest after throwing 1
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