CHICAGO -- The Colorado Rockies' bullpen came through once again, despite a nail-biting finish.
The Rockies, who lead the National League with 40 wins, cobbled the victory and improved to 23-10 on the road.
After starter German Marquez lasted just three innings, five relievers allowed just one hit and one run.
"It was a big day for them," Hanigan said. "The bullpen has been huge for us all year.
"We're in a good groove as a team right now. We've got to get greedy and try to win as many as we can."
But Friday's victory nearly slipped away.
Veteran closer Greg Holland pitched the ninth for his majors-best 23rd save in as many chances despite walking the bases loaded with one out. He escaped by getting Ben Zobrist to pop out and before striking out Jason Heyward.
"Uncharacteristic, really the three walks," manager Bud Black said. "But the good closers know how to navigate through an inning when they need to."
"I didn't have command early in the inning," Holland said. "Luckily, I found it and Hanny walked me through it.
"I've had the bases loaded enough to know you can still wiggle out of it if you make a few pitches."
Blackmon snapped a tie in the fifth with his 14th homer, a shot off Seth Frankoff, who made his major league debut.
Nolan Arenado drove in an insurance run with a single in the seventh and Ian Desmond had three hits.
Heyward had two RBIs as the Cubs lost their third straight following a five-game winning streak.
Marquez's 80-pitch start was pushed back a day to allow bruising on his right thumb to subside. The right-hander allowed two runs -- one earned -- on two hits and three walks before being replaced by Chris Rusin (3-0), who pitched two innings for the win.
Chicago long-relief specialist Mike Montgomery made his first start of the season and went four innings, allowing two runs -- on Hanigan's homer -- and striking out five.
"I wasn't able to those quick outs," Montgomery said. "I knew that I had to battle. The pitch count (73) got up a little bit, but you have to give their team credit for that."
Montgomery started in place of right-hander Kyle Hendricks, who went on the 10-day disabled list on Thursday with tendinitis in his pitching hand. Frankoff (0-1), who pitched two innings following Montgomery, had been recalled to fill Hendricks' roster spot.
All-Star shortstop Addison Russell rejoined the Cubs on Friday after the team told him to take off Thursday's game against the Rockies in the wake of a domestic violence allegation on social media. Russell was available off the bench.
The Cubs took a 2-0 lead in the first inning, scoring one unearned run on a rare Rockies defensive miscue.
With two outs, Anthony Rizzo walked and Zobrist singled. Both came home when Heyward singled up the middle, then advanced to second after Blackmon bobbled the ball in center field and threw wide back to the infield.
Blackmon was charged with just his second error this season.
The Rockies tied it 2-all in the second on Hanigan's second homer, a shot to left.
Aided by a catcher interference call on Hanigan, the Cubs loaded the bases with one out in the third. Marquez escaped the jam by striking out Javier Baez and getting Miguel Montero to fly out to short left.
Colorado moved ahead 4-2 in the fifth on Blackmon's drive to right. Frankoff, recalled to take Hendricks' roster spot, was greeted by Rusin's single. Blackmon then tagged the 28-year-old righty with a towering shot.
The Cubs trimmed it to 4-3 the bottom half of the inning. Rizzo scored from third when Heyward grounded into a force out.
Arenado's sharp single with two outs in the seventh drove in pinch-hitter Raimel Tapia from third to make it 5-3.
NOTES: The Rockies reinstated RHP Adam Ottavino (right shoulder inflammation) from the 10-day disabled list. He pitched a scoreless eighth for his 16th hold. To make room, Colorado sent RHP Carlos Estevez to Triple-A Albuquerque. ... Hendricks said he hope to miss only one start and would be able to rejoin the rotation next week in Pittsburgh. The righty said the "inflammation" in his hand flared up Tuesday after a bullpen session, and that he never experienced a similar injury. Hendricks is 4-3 with a 4.09 ERA in 11 starts after winning 16 games and leading the majors in ERA a year ago. ... Manager Joe Maddon hopes to get Russell, who has struggled at the plate, back into the lineup soon. "We'll just treat him normally and get him back on the field," Maddon said. Russell was accused of "mental and physical" abuse against his wife, Melisa, by someone claiming to be a family friend -- with the Instagram handle @carlierreed -- in a post on a now-removed account. In meeting with media on Friday, Russell said the Cubs had been supportive during the episode.