DENVER -- Where has all the Coors magic gone?

With their 6-2 loss at the hands of the Giants on Sunday, which completed a three-game sweep for San Francisco at Coors Field, the Rockies fell to 3-12 in their last 15 home games. Prior to that stretch, Colorado was 43-20 at the corner of 20th and Blake Street this season.

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The problem? In short: It’s pretty much everything.

“We slowed down a little bit as a group even before the road trip to Philadelphia, Atlanta and Washington,” manager Bud Black said. “We swung the bats very well prior to that and we swung the bats well on that road trip. Since we’ve been back here, we haven’t swung the bats great. … I think it’s a combination of a little bit of a lack of offense, lack of a key hit -- I think you saw that in this series. A little bit of the starting pitching. A little bit of the bullpen.

“To win a game, you need all facets, unless one facet really dominates a game, whether it’s a pitcher throwing a great game or whether you just outslug the other team and win it that way, or you get a key hit at a big moment when you have an opportunity.”

A key hit. A big moment. An opportunity. The Giants had all three come together in one swing of the bat by Brandon Crawford in the top of the ninth inning. After reliever Daniel Bard walked two and gave up a go-ahead single to Tommy La Stella that gave San Francisco a 3-2 lead, Crawford took the second pitch he saw from Tyler Kinley and deposited it just over the wall in left field to break the game open and ensure his club would maintain at least a two-game division lead over the Dodgers with a week to go in the regular season.

Black said the reason he pulled Bard in favor of Kinley in that situation was -- like the Rockies’ weakness in the last 15 home games -- multifaceted.

“Bard has been out there a little bit the last five days,” Black said. “And you could tell that he wasn’t really hitting his spots. He [struck out] Buster Posey and Kris Bryant. After the walk to Steven Duggar and the base hit by La Stella, I thought Kinley would give us a better chance against Crawford. And, you know, Crawford was 2-for-4 against Bard with a homer -- small sample, four at-bats, not a lot. Crawford was 1-for-3 against Kinley, not a lot. It’s too small of a sample size to really make a discernible decision, but I just thought the better matchup to get Crawford out was to go to Kinley.”

Antonio Senzatela was sharp once again, tossing six innings in which he held the Giants’ prolific lineup to two runs on eight hits while walking one and striking out two. The right-hander’s ERA over his last nine starts is 3.00.

“I was just [focused on] getting ground balls against that lineup,” Senzatela said, no doubt tipping his cap to a group of hitters that lead the National League in home runs (237 after Crawford’s ninth-inning shot). “We did that today and I threw a good game.”

The issue on Sunday for the Rockies, as it had been the entire series, was that their own lineup could muster just two runs in each of the three games. Colorado native Kevin Gausman overpowered Rockies hitters for six brilliant innings, in which a C.J. Cron solo homer was the only damage. The Rockies struck out 16 times, one shy of the record for most at Coors Field by Colorado.

The strikeouts are a significant concern for this club, even in an era in which there are more of them than ever.

“In the second half, I think we had done a much better job of that, and then in the last number of games, it’s regressed, that’s for sure,” Black said. “It’s a little bit of a combination of the pitchers we’re facing … and again, it’s that fine line of being aggressive and being able to lay off the borderline strikes. I think that’s what makes the Giants successful, the Dodgers -- those players that they have on their roster have that skill.”

As he continues to shepherd a mostly young and inexperienced group of players, Black knows he’ll see flashes of what can be, but he also knows these days are also part of terrain. As the Giants and Dodgers battle it out for the NL West crown in the next week, he also knows it’s a long way from “here” to “there.”

“Our guys are trying to get there, they really are,” Black said. “ … It doesn’t happen overnight.”