Wednesday's victory, which included Charlie Blackmon's second home run of the season to lead off the third against Cubs starter Jason Berken (0-2), made the Rockies (61-94) two games better than the Cubs (59-96). The teams are candidates for the Majors' second-worst records, with the Astros having run away with the worst record and the No. 1 overall pick in the 2013 MLB First-Year Player Draft.
It had been a long time since Pomeranz (2-9) had shown the form that made him the fifth overall pick in 2010 by the Indians, who sent him to the Rockies as part of the package for right-hander Ubaldo Jimenez last summer. He had gone 13 winless starts since pitching 6 1/3 innings of one-hit ball to beat the Nationals just before the All-Star break. A five-inning stint against the Cubs at Wrigley Field on Aug. 24 was the only time in his last 10 starts he had lasted five innings, which is one of the requirements for a starter to earn a win.
"He threw strikes," Rockies manager Jim Tracy said. "He threw strikes down in the zone. He threw strike one, and as a result of throwing strike one and sending that message, he got himself a couple of first-pitch outs."
Using an effective fastball and the best curveball he had displayed in a while at home, Pomeranz finished with three strikeouts and three walks while throwing 84 pitches in five innings.
"The big thing was just being relaxed," Pomeranz said. "I'd get too tense and that's never a good thing with most things, hitting or pitching. That helped my pitches a lot."
Inefficiency had scuttled many of Pomeranz's outings this season. With Rockies pitchers under a tight pitch count for much of the year, the lack of consistent strikes cost him. On Wednesday, he admitted not being sure he was going to return for the fifth. But Tracy made it a point to have pitching coach Bo McLaughlin tell Pomeranz he was going to give him a chance at the win.
"I didn't know but I had a pretty good fourth inning, and I think that's why they let me go a little bit longer this time," Pomeranz said. "Probably one of my best innings was the fourth."
Pomeranz had some close calls. He walked Joe Mather with two out in the second to load the bases but forced Berken to bounce to the mound, worked Stalin Castro into a grounder to the mound with runners on the corners in the third, and survived Dave Sappelt's one-out double in the fifth by forcing grounders from Darwin Barney and Anthony Rizzo.
No matter what happens in Pomeranz's final start, Wednesday assured that he will end the season with a successful outing fresh in his mind.
"The biggest thing is building on that, knowing what I did today and try to build on that," he said.
The Rockies lineup featuring seven rookies handled the Cubs.
Jordan Pacheco improved his batting average to .307 -- tops among National League rookies -- with two hits, including an RBI double in the two-run first. DJ LeMahieu also added two hits.
The two non-rookies contributed, also. Tyler Colvin's two hits included a first-inning RBI single and Chris Nelson added two singles, one of them driving in two runs.
Alex White pitched the two innings before the skies opened and was helped by a strong throw from Blackmon in right field in the seventh. Runners were at second and third with one out when Blackmon caught Sappelt's fly ball at the warning track, and threw to third in time to nail Joe Mather. Nelson applied the tag before Josh Vitters crossed the plate, so the run did not count.
Cubs manager Dale Sveum was not pleased that Mather was unnecessarily aggressive at a time when the Cubs needed to string hits together.
"It's bonehead plays," Sveum said. "[The players] know they are. It's just not thinking ahead, and Joe has good instincts. He's always been a very instinctive player. For whatever reason, they forget what the score is and the situation. They can't slow the game down to go over all the scenarios before the next play happens."
Reliever Rob Scahill endured a walk and an error in the eighth, and escaped the inning by forcing Castro into a double-play grounder. Scahill also pitched the ninth to preserve the Rockies' seventh shutout of the season.