DENVER -- Paul Maholm has had some rough starts this season. And though Maholm didn't characterize it as such, statistically speaking, this was one of the worst.

Maholm took the mound at Coors Field on Thursday hopeful of going toe-to-toe with National League Cy Young candidate Ubaldo Jimenez. He exited 5 1/3 innings later, left to replay a series of two-out hits that did him in.

"I felt good," Maholm said after the Pirates' 9-3 loss to the Rockies. "They had lost [eight] in a row. They're eventually going to break out. They had good at-bats. You've got to give them credit."

Maholm's problems closing out innings thwarted Pittsburgh's chance to seal its first series sweep on the road in over two years. The Bucs still haven't swept a series in Colorado since 1999, though sound pitching, fielding and hitting in the first two games of this series gave the Pirates at least a chance to end that on Thursday.

Instead, the club watched Jimenez suddenly find his form again as Maholm struggled with his.

It continues to be an up-and-down stretch for Maholm, who has vacilated between both extremes since mid-June. He followed up a career-short, one-inning start with a dominant eight-inning win late last month, only to surrender seven runs in a three-inning outing his next time out. Maholm appeared to be back on track when he came out of the All-Star break and notched the second complete-game shutout of his career.

Then there was Thursday.

"He never seemed like he got into much of a rhythm," manager John Russell said. "The biggest thing was that he had trouble putting hitters away, just didn't quite get the ball where he wanted to. He battled. It just wasn't his day."

Rocked for a season-worst in earned runs (eight) and hits (11), Maholm watched Colorado score the first six of those runs with two outs. A homer by Carlos Gonzalez accounted for the first tally, though it was the Rockies' four-run second that especially stung.

With a runner on first and one out, Pedro Alvarez made a fantastic defensive stop to keep Miguel Olivo's chopper on the infield. But Alvarez's throw sailed over the head of first baseman Garrett Jones and put two Colorado base runners in scoring position.

An on-target throw might have beaten Olivo, but the Rockies' catcher was correctly credited with a hit given how difficult a stop Alvarez had to make. Russell elected to have Maholm intentionally walk Ian Stewart immediately after, preferring to take his chances in a bases-loaded situation with Jimenez.

"We knew we couldn't give up a lot of runs," Russell said, explaining the decision. "If we get to Jimenez, hopefully we get a ground ball. Then you've got [Dexter] Fowler up next, who has been struggling a bit. We took a chance to try and limit it to no runs that inning."

That's not how it turned out.

Maholm struck out Jimenez, but Fowler, mired in a 3-for-44 (.068) slump, ruined all strategy when he followed with a two-run double. Clint Barmes' subsequent two-run single put the Rockies up by four.

"Barmes had a great at-bat," Maholm said. "I kept pounding him in and gave him a changeup, and he barely put it over the shortstop. That was just kind of how the day went."

Maholm skirted around trouble in the next three innings before a pair of sixth-inning singles chased him from a 120-pitch start. That was the most pitches Maholm, now owner of a career 6.26 ERA against the Rockies, has thrown in any outing this season.

"Lately, we've been hitting the ball and getting on base, but we just hadn't been driving in as many runs," Barmes said of the timely hitting. "It was really good, obviously, to be able to drive some runs in and put up the numbers we did today."

More critical than any single game, though, will be Maholm's ability to find some more consistency through the final two months of the season. He hasn't earned consecutive wins all season and has been unable to finish six innings in three of his past seven outings.

On the other end, all of that offense by Colorado provided more than ample support for Jimenez, who entered with a 7.59 July ERA and exited as the first player to reach 16 wins this season.

Pittsburgh used an infield hit and two-out RBI double by Jones to take an early 1-0 advantage. But over the next six innings, Jimenez limited the damage to two lone singles.

"He's not 15-2 with a 2.70 [ERA] for nothing," second baseman Neil Walker said. "When he's throwing his offspeed pitches for strikes that makes his fastball that much more difficult. I'm sure that's a typical day for him today. He did a good job of getting the outs when he needed."

It wasn't until the Rockies were leading, 9-1, and Jimenez was watching from the dugout that the Pirates mustered some additional offensive life. Walker followed Jose Tabata's eighth-inning single with a two-run blast into the right-field seats to cap his five-hit, five-RBI series. The homer was the fifth for Walker this season and second of the series.

Despite watching the Rockies snap a losing streak at their expense, the Pirates did leave Colorado with a rare series win. That wasn't to be understated either, considering the Bucs had accomplished that only once in their previous 10 road series.

"It's obviously disappointing to lose today, but at the same time, to know that you've already won the series is definitely good mentally for you," Walker said. "I don't think we let up today. We fought pretty hard. Jimenez obviously was pretty good today."