The Rockies (53-76), last in the National League West, brought their best month of the season to a close with a 16-13 record. But the Padres (62-71), who are fourth in the division and a spot ahead of the Rockies, also had their best month, at 18-10, having won 10 of their last 11 games.
"They've got a good team, good players -- guys who have waited for their opportunity," Rosario said of the Padres.
Rosario's 23 homers are tied for fourth all-time for a rookie catcher, with Toronto's J.P. Arencibia in 2011 and Geovany Soto with the Cubs in 2008. Rosario is also two behind Todd Helton's Rockies rookie record, set in 1998, and one behind Troy Tulowitzki's performance in 2007.
However, manager Jim Tracy noted that the Rockies were lucky to be close enough to send the winning run to the plate in the ninth. They stranded 10 runners, and their starting pitcher, the struggling Alex White, chucked 76 pitches and lasted just 3 2/3 innings, yet somehow left trailing just 3-0.
"Seventy-six pitches in 3 2/3 innings is not what we're looking for," Tracy said.
Improved pitching has been a key to the Rockies' improvement, but White (2-7) has lagged behind because of inefficiency. White hasn't managed five innings in any of his last five starts. On Friday, he gave up four hits, including Carlos Quentin's 15th homer of the season, and walked three against two strikeouts.
The game's first batter, Everth Cabrera, fought back from a 1-2 count to extend White to 11 pitches before striking out.
But many more at-bats featured White trying to fight from behind in the count. Each deep count brought White closer to the Rockies' management-imposed limitations -- around 75 pitches, and just twice through the order -- especially if the pitcher is laboring.
"It's me, getting behind in counts, throwing a lot of balls," White said. "We've seen me throw 76 pitches through 5, 5 1/3, stuff like that. It's possible. I've just got to get command of the pitches."
Quentin drove in the Padres' fourth run in the fifth inning, when he doubled off Josh Roenicke, after Chase Headley had doubled off Matt Reynolds.
The Rockies scored against Padres starter Clayton Richard (12-12) in the third, when Josh Rutledge doubled with one out and scored on Pacheco's grounder. Pacheco led off the sixth with his homer off Richard, and Rosario followed two batters later with his homer to chase Richard and cut the deficit to 4-3.
"There were a couple of good at-bats from Rosario and Pacheco had a decent night offensively [two RBIs], but we did not put a lot of stressful innings on them offensively," Tracy said.
Rockies reliever Rex Brothers had some misfortune with two on and two out in the eighth. He forced Chris Denorfia into a hard grounder to the middle that Rutledge blocked, but couldn't handle cleanly. Cameron Maybin scored from second for a 5-3 lead.
"The ball rolled away, and that's a long run for both guys," Maybin said. "It was just running with your head up. Before I got to first base, I saw the ball squirt away from him."