DENVER -- Leading 5-2, the Colorado Rockies were looking for an insurance run with two outs in the eighth. Fourteen batters later they were comfortably ahead.
"I'd never seen an inning like that," Cubs manager Lou Piniella said. "We had two outs and two strikes on a hitter and they score 12 runs. I'd never seen an inning like that."
Gonzalez had four hits, two in the eighth when the Rockies set a major league record with 11 straight hits in the inning. The Rockies had 13 hits in the inning, a franchise record.
Fowler and Stewart both hit two-run homers in the eighth as the Rockies piled up a club-high 12 extra base hits in the game.
"That was pretty impressive. There was really nothing flukey to it," Rockies manager Jim Tracy said. "Every ball that got hit was barreled up and hit about as hard as you'd like to see a baseball be hit."
The Rockies batted around twice in the inning against relievers Sean Marshall, Andrew Cashner and Brian Schlitter. Troy Tulowitzki had two doubles and three RBIs, Clint Barmes and Melvin Mora also had two hits and Brad Hawpe and Chris Iannetta reached base twice in the inning.
Every batter got at least one hit in the eighth.
"It was dumbfounding as for us as it was people to watch the game," said Marshall, who gave up five runs in the inning. "You hate to be on the receiving end. I don't think it's going to happen again."
It was a welcome explosion for a Colorado offense that has struggled of late. In the last four games of their losing streak that reached nine Wednesday, the Rockies scored 11 combined runs -- or one less than they did in the eighth inning Friday.
"It's crazy. All the offense coming together when we've been slumping is a blessing," Fowler said.
Jeff Francis (4-3) had his second straight quality start in picking up just his second win since June 13. He gave up two runs and four hits, struck out five and walked one in six innings.
The Cubs have lost three straight and four of five.
"We've getting our lumps lately," Piniella said. "We've been giving up runs in bunches."
Dempster struck out Gonzalez but then walked three consecutive batters to allow Smith to score and make it 3-0.
The Rockies padded the lead in the fifth. Gonzalez led off with his 20th home run, Tulowitzki singled and Hawpe and Iannetta walked to load the bases with no outs.
James Russell relieved Dempster and gave up an RBI single to Stewart to make it 5-0. Russell retired the next three batters to end the rally.
Dempster allowed five runs and seven hits, struck out five and walked five in four-plus innings.
"I wasn't aggressive. It was embarrassing," Dempster said. "I would rather have given up the 11-straight hits than to not be aggressive."
The Cubs reinstated RHP Carlos Zambrano from the restricted list. Zambrano was placed on the restricted list June 29 after getting into a verbal altercation with teammates during a June 26 game against the White Sox. ... Piniella will miss the last two games of the series and the opener of the home series with Milwaukee on Monday to attend his uncle's funeral in Tampa. Bench coach Alan Trammell will manage the team in Piniella's absence. ... Rockies 1B Todd Helton (back stiffness) began a rehab assignment with the Casper Ghosts of the Rookie League.