De La Rosa took a one-hit shutout into the sixth inning in beating San Diego for the sixth straight time and Blackmon, recalled from Triple-A on Monday, drove in the winning run and made a spectacular defensive play to help Colorado to a 5-4 win over the Padres on Wednesday night.
De La Rosa lifted his record at Petco Park to 3-0 with a 1.88 ERA. His winning streak against San Diego spans eight starts.
Blackmon matched a career-high with two RBIs and his triple in the eighth off Padres reliever Nick Vincent gave the Rockies a 5-3 lead. He also had an RBI single in the sixth.
Blackmon also made a diving catch on pinch hitter Mark Kotsay's sinking liner to center with two runners on in the Padres' sixth after Carlos Quentin had hit a two-run home run off De La Rosa to make it 4-2 and send the Rockies' starter to the clubhouse.
"With the guys out of the lineup sometimes you got to win games that way," Rockies manager Walt Weiss said. "It's nice to see us do that. Charlie had some big hits and made some big plays. Jonny (Herrera) had a really good series. Any time you win a series in your division on the road it's really big."
All eight position players for the Rockies had at least one hit and Colorado outhit San Diego 13-7.
Herrera drove in the Rockies' first run with a sacrifice fly off Andrew Cashner in the second inning. And his drag bunt single led to the Rockies' fourth run in the sixth on Blackmon's single.
The Rockies were leading 4-0 in the sixth when Quentin hit his 11th home run, a two-run shot to straight away center field, scoring Chase Headley, who had walked. That was all for De La Rosa (9-5), who allowed two hits over five innings with four walks and four strikeouts.
"We couldn't get to De La Rosa until Q's homer," Padres manager Bud Black said. "He kept us in check. We couldn't mount any attack against him. He did a good job of keeping the ball down and changing speed. The change/split is a very effective pitch. The fastball, change combo was also effective."
The Rockies came back with an insurance run in the eighth off Padres reliever Nick Vincent when Blackmon tripled to score pinch hitter Corey Dickerson, who had singled with one out.
"I'm very thankful that the Rockies got enough faith in me to put me in this position (and) to have an opportunity," Blackmon said. "I'm just blessed to be healthy and be here, and it really feels good to help be a part of a team win."
Rockies reliever Rex Brothers pitched a scoreless eighth and Rafael Betancourt came on in the ninth to pick up his 13th save in 14 opportunities. Betancourt gave up an RBI single to Headley, who stole second to put the tying run in scoring position with two out. However, Betancourt got Quentin to pop out to first in foul territory to end the game.
Cashner (5-5) went five innings for the Padres, giving up three runs, two earned, on eight hits. He struck out five, walked two and threw a wild pitch that led to a Rockies run in the fifth.
Helton drove in the Rockies' second run with a single in the third that scored D.J. LeMahieu from second.
D.J. LeMahieu, who had two hits, reached on an error by Padres shortstop Cabrera leading off the fifth. Carlos Gonzalez, who returned after missing two games with an injured middle right finger, singled up the middle, nearly hitting Cashner. Michael Cuddyer hit a grounder that forced Gonzalez at second.
With runners on first and third, Cashner struck out Helton. However, Cashner uncorked a wild pitch with Nolan Arenado at the plate, allowing LeMahieu to score.
The Rockies left 12 runners on base.
Rockies OF Dexter Fowler and SS Troy Tulowitzki were expected to rejoin the team Thursday in Los Angeles. Rockies manager Walt Weiss said that Fowler, who has been on the DL with a right bone bruise since June 26, would play Thursday against the Dodgers and that Tulowitzki, sidelined with a fractured right rib since June 14, could be activated during the four-game series. . Weiss also noted that pitcher Juan Nicasio would be recalled from Triple-A Colorado Springs and would pitch Friday against the Dodgers and Clayton Kershaw. . Padres manager Bud Black announced that the Padres plan to purchase the contract of 25-year-old RHP Sean O'Sullivan from Triple-A Tucson and he will pitch against the San Francisco Giants on Friday night. O'Sullivan is 7-4 with a 3.88 ERA in 18 starts for Tucson. He has a 6.31 ERA in 43 major league games with the Angels (2009-10) and Royals (2010-11). . Padres 1B Yonder Alonso (right hand fracture) went 4 for 4 with two RBIs Tuesday in a rehab assignment with Tucson and could be activated during the four-game series with the Giants. . Padres 2B Jedd Gyorko, on the DL since June 10 with a right groin strain, began his rehab assignment with Single-A Lake Elsinore Wednesday. Black said that Gyorko could be moved up to Triple-A Tucson Thursday or Friday.