The D-backs took two of three from the Phillies at Chase Field last weekend and the win on Monday helped them start off a three-city, 11-game road trip on the right foot.
LaRoche got the D-backs started early when he smacked a three-run homer in the first inning off Jason Hammel.
"I don't know if he was going to go in or out," LaRoche said, "but he obviously missed with his spot, and I was able to get some good wood on it."
The homer was set up when Justin Upton drew a two-out walk and Mark Reynolds followed with a single.
"We took advantage of Hammel getting a little erratic, and that's good team offense," D-backs manager A.J. Hinch said.
Spotting Dan Haren a three-run lead is usually a good recipe for success and Monday was no different.
Coming off an outing in which he allowed seven earned runs in six innings, Haren gave up a leadoff homer to Carlos Gonzalez and then kept the Rockies off the board until the eighth.
"I made a decent pitch to Gonzalez, and he hit it out," said Haren, who improved to 3-1. "From that point on, I made a few adjustments. My stuff was pretty good all night, and I had the lead all night, so I was able to be real aggressive."
Meanwhile, the the D-backs' offense tacked on a pair of runs in the second to extend their lead to 5-1.
The Rockies' really did not threaten against Haren in innings two through seven, never getting more than one man on base at a time.
"It was pretty interesting the way that game played out," Hinch said. "Early on, we showed a lot of offense, which is something we haven't done a ton of early in games, and then they pitched us pretty tough after that. To be able to hold them off for that long, I thought Danny did a great job of competing. He was a little erratic early with his control, it's not normal for him, but he battled through it, kind of slowed himself down a little bit and got through eight innings."
In the eighth, the Rockies finally got to Haren again when Eric Young Jr. hit a one-out, pinch-hit double and came around to score when Gonzalez followed with a single to center.
Haren, though, was able to get pinch-hitter Ryan Spilborghs to ground into an inning-ending double play.
"I'm still kind of fighting myself," Haren said. "My secondary pitches are there, my curveball, cutter and my split have been really good this year, but just kind of fighting myself with fastball location. I still can get a lot better."
Naturally, the ninth inning, which has seen so much heartbreak for the D-backs this year, was a challenge.
Closer Chad Qualls walked Todd Helton to start it and then after striking out a pair, he allowed back-to-back singles, the second of which scored Helton and pulled the Rockies to within 5-3.
Qualls, though, was able to close it out as he fanned pinch-hitter Jason Giambi to end the game.
"That's a good win," Hinch said. "That's a good way to continue the momentum, based on what we did at home."