DENVER -- A month and a day into their season, the Rockies have seen plenty of promising threads. But their inability to string those elements together and weave their season into a pattern of success has left them too often disappointed in themselves.

One of the best individuals at bringing his "A" game out and putting quality efforts back-to-back has been starting pitcher Jason Marquis, who threw a complete game five days ago in San Francisco.

Marquis' dominant stretch of starts at Coors Field finally came to end on Thursday, however, as the Rockies right-hander battled into the seventh inning in an 8-3 loss to the Giants, his first defeat in seven career starts in Denver.

"I didn't execute where I needed to," Marquis said. "[Giants starter] Matt Cain threw the ball good and kept us in check. A couple plays got away from me on the bunt plays. It was just one of those days where I didn't execute when I needed to."

Marquis (4-2) has used a sinking fastball to earn his success this season, but the sink had a touch too much float to it Thursday, and the Giants touched him for eight hits and seven runs (five earned) in his six-plus innings on the hill.

"[His sinker was] a bit off," manager Clint Hurdle said. "He still rolled 13 ground ball outs, but there were some pitches up that got hit. They were able to go ahead and score runs. That was the big difference. We've got to put together a better game with more consistency. You got [an] 11-1 [win] last night, you come in, and we're underneath again, so you got to fight your way back."

Marquis gutted it out into the seventh and was relatively efficient with 87 pitches thrown, but he wasn't fooling the Giants as he had five days earlier in their park. He had enough command to avoid walking a batter, but in each of three innings where the first batter reached base, Marquis gave up a run or more.

The two decisive innings for the Giants each included errors by Marquis and an assortment of oddball plays and tough rolls. The four-run third saw Cain lace a single into right past Todd Helton, and Fred Lewis drive a single into left before Marquis overthrew to third on a fielder's choice grounder from Emmanuel Burriss. Bengie Molina lifted his second homer of the game into the right-field seats, after hitting a solo homer to the gap in left-center to lead off the second.

Marquis was tagged for two more runs in the seventh, both unearned. He yielded a leadoff single from Nate Schierholtz, then fumbled a bunt from Cain, pulling Helton off the bag at first with an errant throw. Lewis singled home a run, and Molina plated his fourth run of the day on a grounder to third.

"Obviously, they know what I'm going to attack them with," Marquis said. "But I still need to execute, still got to make pitches. The movement, action [on my pitches] was fine. I left a few balls up in the zone. A couple ground balls got through. Those two errors were costly, but I still got to make pitches after the fact. It's just one of those days."

The Rockies were unable to get anything off of Cain (3-1) in his six innings pitched, getting a solitary hit from Helton and drawing five walks without being able to capitalize on the opportunities.

"Cain threw very well," second baseman Clint Barmes said. "He was pretty effective when he needed to be. He might have gotten behind some hitters, but he came back, and if we did hit him, we either didn't hit it hard, or we hit it right to somebody. It didn't really matter what Marquis did today. We didn't score any runs. And we didn't swing the bats very well.

"It was definitely pretty disappointing. Personally, I'm not really happy with myself. Could have had some better at bats. It seems like we've had a lot of those games this year, and it needs to turn around some time soon."

Colorado got on the scoreboard in the bottom of the seventh when Brad Hawpe sent southpaw Jeremy Affeldt's full-count, four-seam fastball sailing into the left-field seats for his fourth homer of the year.

Ian Stewart followed with a two-run shot to right with two outs in the bottom of the ninth, but the climb back into the game to make up a seven-run deficit was too steep at that point.

"We didn't do much to help ourselves today, across the board," Hurdle summed up. "We weren't able to bring a lot of offense. We had people out there in a couple of opportunities that could have sparked something and maybe gotten us rolling on offense, but that didn't happen. Some situations defensively, we didn't handle well that led to extended innings. And Molina ran a couple balls out of the ballpark on us."

While the Rockies have had trouble putting the complete package together from game to game with enough consistency to win more than two of the 10 series they've played this season, it's rare for the club's pitching, offense and defense -- which committed as many errors (three) as the Rockies produced runs -- all to go at once, as in this game.

"We've got to find a way to take care of what we can take care of," Hurdle said. "When we have opportunities on offense, we've got to shut them down, and we got to make plays defensively. If we make some plays defensively today, the game's a lot tighter, and who knows what might happen. We might be able to spark something if we were able to handle the ball on the defensive side."