Hosmer's homer was one of five for the Padres, who rank second in the majors with 66 this season. Jake Cronenworth added a two-run drive in the seventh before Jurickson Profar and Trent Grisham lined solo shots in the eighth. Josh Naylor finished it off with a towering two-run homer in the ninth.
''I don't think I've been on an offense that's been rolling this good,'' Hosmer said.
Paddack (3-3) pounded the strike zone in picking up his first win since Aug. 3. The right-hander threw 60 of 85 pitches for strikes, allowing five hits and two unearned runs while striking out eight.
For that, Paddack credited tunnel vision - he only focused on catcher Austin Hedges' glove as he made his first start at Coors Field. That along with keeping his fastball low led to a successful outing.
''Our game plan was to be efficient today,'' Paddack explained.
He was at that.
''He was due for an outing like this,'' Hosmer said. ''He's too good of a pitcher not to have an outing like this after a couple that he let get away.''
Designated hitter Manny Machado extended his hitting streak to 12 games with two singles. Fernando Tatis Jr. had another big day with three hits, including two doubles. He also was hit by a pitch.
The Padres powered their way to the win with their 19th multi-homer game.
Waiting in the wings, even more power.
San Diego acquired slugger Mitch Moreland in a trade with Boston on Sunday morning. He was leading the Red Sox in homers with eight.
''Mitch is rolling right now. We're rolling as a team right now,'' Hosmer said. ''It's perfect to add a bat like him in there. He's a proven guy.''
All the Rockies not named Nolan Arenado struggled to solve Paddack and a procession of relievers. The Padres struck out Trevor Story four times and held Charlie Blackmon hitless in three at-bats. Blackmon is 0 for 12 in the series, dropping his batting average to .354.
Arenado had two of Colorado's seven hits.
Rockies starter Ryan Castellani (1-2) was roughed up in two innings. He gave up five runs.
Castellani pinned his struggles on an ineffective changeup.
''That's been a huge pitch for me in all my starts,'' he said. ''Just kind of not having that today hurt me.''
San Diego has taken two of three in this pivotal four-game series. Colorado is right behind San Diego in the NL West race. Both are chasing first-place Los Angeles.
''We're fired up,'' Paddack said. ''We're rolling. We have a lot of confidence.''
Padres: Manager Jayce Tingler had no update on lefty Adrian Morejon, who was scratched as a starter over the weekend and placed on the 10-day injured list. The team did not specify the reason.
Rockies: OF David Dahl (lower back soreness) is expected to take some at-bats at the team's alternate site Monday. ''He's feeling better,'' manager Bud Black said.
Colorado acquired right-handed reliever Mychal Givens from Baltimore for prospects and cash.
''We're just really excited to bring in this caliber of pitcher into the fold,'' Rockies general manager Jeff Bridich said.
A two-out error opened the door for the Rockies to score two in the sixth. Hosmer fielded a grounder at first and tried to go to second, but Tatis couldn't handle the throw as the shortstop ran toward the bag. The error was charged to Hosmer.
The Padres optioned right-hander Michel Baez to the alternate training site to make room for new reliever Trevor Rosenthal.
No surprise that Rockies first baseman Josh Fuentes is familiar with catching Arenado's throws.
They are cousins.
Growing up, they spent hours and hours together playing everything from backyard baseball to Whiffle ball.
''It definitely correlates,'' Fuentes said. ''I'm always reading his throws.''
Fuentes, who's also a third baseman, doesn't get much time at the hot corner with Arenado around - even in practice.
''He would never go to first,'' Fuentes cracked. ''I don't think he ever wants to go there.''
Fuentes switched to third late when Arenado exited the lopsided loss.
The Rockies will throw right-hander German Marquez (2-4, 4.50) on Monday to close out the four-game series. The Padres announced they will start Garrett Richards.
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