PITTSBURGH -- Gregory Polanco preserved a tie in the top of eighth inning then sealed a win for his team in the home half.

Colorado shortstop Jose Reyes tagged from third with one out on third baseman Nolan Arenado’s fly-ball to right field. The Pirates right fielder snagged the fly on the run then fired home to nail Reyes, the potential go-ahead run.

Pinch-hitter Josh Harrison drove in the game-winning run with a single in the home half inning and Polanco put the game away with a RBI single, one of his three hits Friday, as the Pittsburgh Pirates outlasted the Colorado Rockies 5-3 on Friday.

“I know he's fast,” Polanco said of Reyes. “I just try to put a good throw in there and not do too much with it, just try to put a good throw in there.”

Colorado manager Walt Weiss didn’t second-guess Reyes’ decision.

“I was glad he took off,” Weiss said, “it took a great throw by Polanco. It was right on the money and it wasn’t real deep but I thought certainly deep enough for Reyes to take a shot.”

Catcher Francisco Cervelli and first baseman Pedro Alvarez each walked with one out. Cervelli moved to third on pinch-hitter Aramis Ramirez's fly-out then broke a 3-3 tie on Harrison's single.

Polanco followed with a single to center to score pinch-runner Sean Rodriguez and insure Pittsburgh's late lead.

“Anytime you get a chance to help the team you want to be a part of it,” Harrison said.

“That's what makes it so good. It's a different guy every night.”

Harrison, a regular earlier this season prior to a thumb injury, rejoined the Pirates last week as a group of players offering manager Clint Hurdle more versatility in managing his infield personnel. The Pirates traded for Aramis Ramirez at the deadline and the addition of Jung Ho Kang, the July NL Rookie of the Month, has paid massive dividends.

“We're going to have better options during the course of the game than we've ever had since I've been here,” Hurdle said. “We can leverage matchups, skill sets.”

Colorado tied the score twice Friday but was unable to take a lead against the Pirates.

“I think it’s a well-rounded team,” Weiss said. “There’s not many holes. They can beat you a number of ways and they’ve got a real good bullpen.”

Left-hander Tony Watson (3-1) pitched a scoreless eighth to earn the win while right-hander Mark Melancon picked up his 42nd save with a perfect ninth.

Colorado right-hander Scott Oberg (3-3) was charged with the loss after giving up two runs in the eighth. His outing broke a streak of 18 2/3 consecutive scoreless tossed by the Rockies bullpen.

“Bullpen has done a nice job here lately,” Weiss said. “Two walks, that’s going to hurt you late in the game.”

Right fielder Carlos Gonzalez tied the game at 3-3 in the sixth with his 31st home run of the year to right-center. Gonzalez preserved the tie in the home sixth when he laid out to catch Polanco's low line drive with the bases loaded and two outs.

Pittsburgh left-hander Francisco Liriano exited after the sixth. The Pirates have won each of his last 11 starts.

Liriano gave up three runs and four hits. He walked three and struck out five.

Colorado right-hander Jon Gray, the No. 3-overall choice in 2013, remains in search of his first career win after he took a no-decision in his fifth start as a major-leaguer.

Gray yielded three runs and seven hits in 4 1/3 innings. He walked two and struck out six and bounced back after he gave up seven runs in 1 2/3 innings against the Mets Aug. 21.

“I was okay with it,” Gray said of his outing. “It was a lot of stuff I can’t control but I think I was battling pretty well.”

NOTES: Colorado selected the contract LHP Jason Gurka from Triple-A Albuquerque. The Rockies optioned LHP Tommy Kahnle to Triple-A Albuquerque and designated LHP Kenny Roberts for assignment. Gurka posted a 2.86 ERA over 63 innings between Albuquerque and Double-A New Britain this season. ... Pittsburgh played Colorado for the first time in 2015. The Rockies were the only National League team the Pirates were yet to face. ... Rockies CF Charlie Blackmon was out of the starting lineup with an extra day off after Colorado's off-day Thursday. Blackmon played in each of Colorado's 37 games since the All-Star Break.