DENVER -- The Pirates took advantage of the thin mountain air at Coors Field on Wednesday. Over and over and over and over again.
The Pirates belted four home runs in a game for the fourth time this season and rallied from an early deficit to beat the Rockies, 9-6.
"You never know at this park," said Garrett Jones, who hit his 13th home run of the season. "You're never out of any game. Popups can turn into home runs, and you can score a bunch of runs here."
Though four-home run games have been common this year, it happened only three times in the three previous seasons combined. The previous time the Pirates had four games with four home runs or more in a season was 2000.
"We're trying to do damage up there, and a lot of guys' swings are coming around," Jones said.
The offensive outburst helped the Pirates (51-40) compensate after a rough start from James McDonald, whom the Rockies rolled for six earned runs in a five-inning outing. By contrast, McDonald allowed six earned runs total in five starts in May.
Despite the lopsided line, McDonald earned the win to reach the 10-victory mark for the first time in his career.
"It's weird because I got my first big league win here," he said.
McDonald said he was not aggressive enough against Colorado's hitters early in the game as the Rockies raced out to a 5-1 lead. After the second inning, he started attacking batters the way he did in the first half of the season, when he established himself as the Pirates' ace.
He also struggled with his command early and pitched himself into hitter's counts.
"When you get behind hitters here, it's not going to be good," he said.
It was the second consecutive lackluster performance from McDonald, who allowed five runs, four earned in less than five innings last week against the Milwaukee Brewers at Miller Park, also a hitter's haven.
"He's still growing up," manager Clint Hurdle said. "This is his second season with us, the first full season in the rotation. The first half was so clean and efficient that the league fires back. And when you're not sharp, you pay."
Hurdle said the coaching staff has identified a "couple things we put our fingertip on" that might have contributed to McDonald's recent inconsistencies.
The Pirates surged ahead with a swarm of home runs, scoring nine runs on 11 hits.
And they did it all without a hit from their two top batters -- Andrew McCutchen and Neil Walker, who combined to go 0 for 8. Walker's hitting streak was snapped at 17 games, one short of his career high.
"For it to not happen for those two and the other guys responding, it's just another good sign of this team finding different ways to win games," Hurdle said.
It was the 20th series loss of the season for Colorado (35-56).
The Pirates pounded Rockies starter Jeremy Guthrie, and chased him from the game before the end of the third inning. He allowed six runs, four earned, on six hits in 22/3 innings, his shortest start of the season.
The Pirates erased a four-run deficit in the third inning with a couple big hits and a couple key assists.
Jones hit a two-out, three-run homer that pulled the Pirates within one run, connecting with an 85 mph changeup and planting it among the trees in the Pirates bullpen.
An error, a single and a hit batter loaded the bases for Clint Barmes, who looped a single into right-center field that scored two and gave the Pirates a 6-5 lead.
A pair of home runs in the fifth inning allowed the Pirates to maintain the lead for good. Casey McGehee cranked his eighth of the season, a two-run shot that barely cleared the 17-foot-tall fence in right field. Two batters later, Rod Barajas hit his eighth this season as the Pirates climbed ahead, 9-6.
"It's nice to jump back in a game and take the life out of the other team with one swing of the bat," McGehee said. "The big thing is we went up there and didn't try to drive the ball out of the ballpark. We just made good solid contact and let the ball travel the way it can here."
In his first game this season, Rockies outfielder Andrew Brown went 3 for 5 with a double and two RBIs, including one in the fourth inning that tied the score, 6-6.
Things did not start off well for McDonald, who threw only three of his first 11 pitches for strikes. Two of those landed on the wrong side of the outfield wall as the Rockies grabbed a 3-0 lead before McDonald recorded an out.
Michael Sanserino: firstname.lastname@example.org, 412-263-1722 and Twitter @msanserino.