Capuano (10-7) surrendered a pair of runs in the first inning and two more in the third, when Garrett Atkins and Matt Holliday combined for the Rockies' second set of back-to-back home runs this season. That was enough for Colorado sinkerballer Aaron Cook (7-9), who limited the Brewers to four hits in eight solid innings, and Brian Fuentes, who logged his 20th save.
Milwaukee lost for the ninth time in its last 12 games away from Miller Park and needs to sweep the next two games to avoid a fifth straight road series loss.
"I don't know what it is," said shortstop Bill Hall, one of six Brewers held hitless. "I can't pinpoint it. We feel the same, we look the same, we just don't get it done as much on the road as we do at home."
The Brewers are 32-23 at Miller Park, the most home wins of any team in the National League. But with Monday's loss they slipped to 18-33 everywhere else, the second-fewest road wins to last-place Pittsburgh (13).
Making matters worse, the Rockies are one of four teams standing between the Brewers and the National League Wild Card-leading Reds. The Reds were idle on Monday, so the Brewers fell to 5 1/2 games back.
"It seems like everybody is right there," Brewers manager Ned Yost said. "You don't really try to look at it as, 'They're there with us, we've got to beat them.' We've got to win. If you win, everything takes care of itself. Every time we step on that field, it's a very, very important game."
Cook certainly had something to do with the Brewers' continuing struggles. In eight innings, he surrendered two runs on four hits, three walks and four strikeouts. Damian Miller drove in the Brewers' first run with a second-inning single, and he scored the second on Prince Fielder's sacrifice fly in the fifth.
The Brewers, trailing 4-2 at that point, nearly put together a big inning. But with the bases loaded and one out, left fielder Holliday caught a sinking Fielder line drive that went for a sac fly instead of a potential bases-clearing hit.
At two hours, six minutes, it was the fastest nine-inning game in the 12-year history of Coors Field.
"I had no idea," Hall said. "I knew we weren't getting a lot of hits and neither we're they. I never knew it was a record-breaking game."
Said Yost: "That's what happens when both pitchers are really on, banging strikes."
Holliday and Todd Helton hit run-scoring singles in the first inning -- Holliday's on a low and away pitch and Helton's an infield smash that glanced off third baseman David Bell's glove. In the third, Atkins hit a two-out home run for a 3-1 Rockies lead, and Holliday took the next pitch to the right-field seats to make it 4-1. Capuano settled in to retire 16 of the final 18 batters he faced, surrendering only a Clint Barmes two-out double in the fifth inning and another in the eighth.
"Cappy, for me, only made two bad pitches all night," Yost said. "One that was the leadoff double to [Jamey] Carroll and the one to Atkins that he hit nine miles."
Still, it was a step forward for Capuano, who had 10 wins at the All-Star break and was a late addition to the NL squad. In three post-break starts, he was 0-2 with an 8.22 ERA (14 earned runs in 15 1/3 innings). He entered Monday tied with the Diamondbacks' Brandon Webb and the Yankees' Mike Mussina for tops in the Majors with 18 quality starts -- six or more innings and three or fewer earned runs -- but only one of his four starts since the break fall into that category.
"Physically, I feel really good," Capuano said. "Especially towards the middle and the end, I was hitting all my pitches and starting to throw the ball a lot better than I have been during the whole month of July. That was a tough game to lose out there, but I feel good and I'm really looking forward to the month of August."
If the Brewers can't get it going on the road, he might be the only one.