DENVER — When Nolan Arenado flashed some impressive glove work to help get out of a bases-loaded jam in the fifth it looked like the Colorado Rockies' day.
Five pitches into the eighth, it turned out to be Pittsburgh's afternoon.
Josh Harrison had four hits, including a tiebreaking homer, to help the Pirates beat Colorado 7-5 on Sunday.
The loss denied the Rockies their first winning homestand in two months.
"If we won today we would have gone 4-2 on the homestand but it is what it is," Arenado said. "We were able to split and we won the series."
Harrison ended that hope when he homered on reliever Rex Brothers' first pitch of the eighth to break a tie, and Polanco followed with his fifth of the season to make it 7-5.
After Rockies pitchers held the Pirates to two runs in the first two games Brothers (3-5) allowed two in a matter of moments to add to his frustrating season. He has allowed six home runs in 42 innings after giving up five in 2013.
"I can't explain it, to be honest," he said. "The way we've played the last couple of days and to go out there and do that today, I really can't put it into words."
Harrison also had helped give the Pirates a 5-4 lead. In the sixth he swiped second but was caught in a rundown when he slid past the bag. He survived to reach third — giving him two stolen bases on the play — and scored on a pinch-hit double by Ike Davis to make it 5-4.
"We've got to get an out there," manager Walt Weiss said. "I look at a rundown as a free out. Harrison's one of the tougher guys to put away in a rundown but we've got to get the out there. It was a good play."
Snider had tied the game with a pinch-hit, two-run homer earlier in the inning.
Arenado tied it 5-5 with a homer in the seventh, his ninth of the year and second in as many games before Harrison and Polanco struck in the eighth.
"The back-to-back homers hurt us but we felt good all the way to the ninth inning," Arenado said. "Melancon came in and did what he did all year. We weren't able to finish off there."
Pittsburgh starter Edison Volquez has struggled against Colorado and at Coors Field. He entered Sunday 3-8 with a 7.80 ERA in 13 career starts against the Rockies. The numbers are even worse in Denver where he was 1-5 with a 8.45 ERA in eight career starts.
He didn't improve those statistics Sunday. He allowed an RBI single to DJ LeMahieu in the second inning and a two-run homer to Barnes as part of a three-run fourth inning, although only one of the runs was earned.
He left after loading the bases with one out in the fifth. Reliever Jared Hughes got Barnes to hit into an inning-ending double play.
Rockies starter Franklin Morales didn't fare any better. He labored through four-plus innings, allowing two runs on six hits and walking five. He left after issuing two walks to leadoff the fifth. The Rockies got out of a bases-loaded, no-out jam when Arenado snared Jody Mercer's liner and tagged third for a double play and Neil Walker grounded out.
"Good play by Nolan. He had some big hits, Barnes had a big hit," Weiss said. "There were some things that made you think we would put that game away."
NOTES: Rockies SS Troy Tulowitzki (left hip flexor strain) flew to Philadelphia on Saturday to have his hip checked by Dr. William Meyers. Meyers operated on Tulowitzki's injured groin in 2012. Tulowitzki was spotted in the stands behind home plate at Yankees Stadium on Sunday. ... Rockies 1B Justin Morneau (neck injury) will play for Triple-A Colorado Springs on Monday and could be activated Tuesday. ... Colorado LHP Yohan Flande (0-2, 7.20) will start against the Cubs in Chicago on Monday.