DENVER -- The first three innings of Tuesday’s series opener between the Giants and Rockies looked deceptively like a pitchers’ duel, with the game scoreless through three and with each team notching a couple of hits. But while Rockies starter Dakota Hudson walked five and left the game in the fourth with 95 pitches, Giants stopper Kyle Harrison cruised efficiently through the Rockies' lineup to set up a gem of a game, needing just 86 pitches to get through seven scoreless innings en route to a 5-0 win for the Giants.

Harrison was the sixth Giants starter to throw seven scoreless innings at Coors Field, and the first in 12 years. The five previous pitchers make up a murderer’s row of mound masters: Barry Zito (April 9, 2012), Tim Lincecum (June 11, 2008), Matt Cain (April 17, 2007), Jason Schmidt (July 17, 2004) and Russ Ortiz (Aug. 28, 2002).

The beyond-quality start was desperately needed as the Giants came to Denver with a 1-6 record on their road trip, with no starter lasting six innings and Harrison’s previous start marking the only time a pitcher had gone five complete innings on the trip.

“A hundred percent that's something that I want to be,” Harrison said of his emerging role as an inning-eating stopper. “I came up last year and saw Logan [Webb] and all these guys doing that. So that's something that I kind of wanted to get to. We got the ‘W,’ so that's all that matters at the end of the day.”

Harrison has yet to pitch following a Giants win, and the team is now 6-2 in games he’s started.

“It's huge to go out and go seven scoreless,” shortstop Nick Ahmed said. “It just gives us confidence knowing that he's out throwing strikes and keeping them scoreless, and for us to not feel like we need to score a ton of runs to win a game. It's nice to know you're going to score a few and he's going to hold the lead for us.”

The difference was the fourth inning, when San Francisco piled on, putting four hits and a walk together for a four-run frame. Matt Chapman sparked the rally with a one-out walk, and Blake Sabol followed with a single to right. Ahmed and Jung Hoo Lee hit identical dribblers down the third-base line. Third baseman Ryan McMahon barehanded both, but he lost Ahmed’s ball and ran out of time to catch Lee as both recorded infield singles to load the bases.

A grounder to second from Thairo Estrada plated Sabol and drove Hudson from the game, and a single to center from LaMonte Wade Jr. off reliever Ty Blach brought Ahmed and Lee home to cap the big inning.

“Guys are grinding with two strikes,” Ahmed said. “We had some good at-bats tonight. Sometimes it's not the three-run homer that wins the game.”

Harrison was making his Coors Field debut, and you couldn’t ask for a better first impression.

“When you haven't pitched here before, there's some unknowns when you go out there,” manager Bob Melvin said. “Is your breaking ball going to break like it normally does? Am I going to get winded? There's some uncertainty, but it didn't seem to bother him at all.”

Though he appreciated the individualized canisters of oxygen the Giants brought to Coors Field, Harrison said he didn’t feel affected by the altitude when it came to executing his pitches.

“I played a lot of Minor League games in Salt Lake and Reno and all these places, so I have no excuse to not show up on this day,” Harrison said. “I felt great out there. The shape of the pitches were fine, honestly.”

The Giants added an insurance run in the seventh, but they didn’t need it. Harrison left after seven strong innings, allowing just four hits and two walks while striking out two. He only allowed one Rockies baserunner to reach second all night.

The win followed Melvin’s closed-door meeting for a rare talk Monday after being swept by the Phillies, and Ahmed thought the team responded well.

“We needed to hear it,” Ahmed said. “We didn't play well in Philly, obviously. We got embarrassed. They're a good team, but we didn't play our best baseball. We just came out [tonight] and did the little things right. You're not going to always win a game like that, but you give yourself a better chance.”