Since the Colorado Rockies began deploying their four-man rotation, Drew Pomeranz has had trouble picking up wins.
On Friday, Pomeranz was in line for his first win since July 6, but the Chicago Cubs rallied for three runs in the eighth inning to win the opener of a three-game series, 5-3.
Brett Jackson crushed a game-tying home run and Joe Mather delivered a go- ahead single to earn the Cubs their fifth win in their last 23 games.
Pomeranz picked up no decision after holding the Cubs to two runs on two hits in five innings. He struck out one and walked one as he has now gone eight starts without a victory.
Carlos Gonzalez slammed his 21st home run, but the Rockies saw their five-game win streak come to an end.
"It's a tough loss, but we can't let that affect us," Gonzalez said. "We've been doing a great job. We just need to continue the way we've been playing."
Jackson crushed a no-doubt solo shot to right field off Matt Belisle (3-5), just the Cubs' third hit of the afternoon, to tie the game at three in the eighth inning.
"It was very nice to get that first Wrigley homer," Jackson said.
After Darwin Barney grounded out, Luis Valbuena laced a double into the left- field gap. Joe Mather followed with a base hit to right field, scoring Valbuena and giving the Cubs their first lead of the day.
Chicago added a third run in the eighth inning after DJ LeMahieu missed a catch at second base, putting runners on the corners, and pitcher Matt Reynolds delivered an errant throw to first base on a dribbler back to the mound, which scored Mather.
Carlos Marmol worked around a one-out double in the ninth to successfully close out his 15th straight save opportunity and earn his 16th save of the year.
The Rockies went ahead on an unearned run in the first. Starlin Castro misplayed Jonathan Herrera's ground ball with one out. Herrera moved to second on Jordan Pacheco's base hit and to third on Gonzalez's ground out. He scored when Jeff Samardzija uncorked a wild pitch.
"To come out early like that and scuffle and really not have fastball command or a slider all game and to get through those seven innings felt really good," said Samardzija.
Chris Nelson hammered a high fastball into the seats in left-center field to give Colorado a 2-0 lead in the second and Gonzalez led off the third when he crushed a 3-1 fastball out to center field to expand the lead to three.
The Cubs picked up their first two hits in the fifth. Alfonso Soriano hit a 3-1 fastball over the left-center field fence and Welington Castillo slammed another solo homer to bring the Cubs within a run.
Soriano has 16 RBI in his last 17 games ... Samardzija received a no decision after allowing three runs -- two earned -- on six hits with seven strikeouts in seven innings ... Samardzija has received two or fewer runs of support in eight of his last nine starts ... Colorado's bullpen had allowed two earned runs in 23 innings over its last five games. On Friday, the Rockies bullpen surrendered three runs -- two earned -- in three innings ... The Rockies went 0-for-6 with runners in scoring position.