Matt Cain, usually calm on the mound, jawed at Matt Holliday after he showed emotion following his home run in the third. Jamey Wright was ejected in the eighth for hitting Holliday, and manager Felipe Alou was tossed, too, when he argued with plate umpire Rick Reed.
"I let my emotions get the better of me," Cain said after the Giants' fourth loss in a row. "I take fault for it."
Even the usually mild-mannered Alou wasn't his usual self after the game.
"I've answered that one 10 times. We've been in a must-win situation for 10 days," Alou said. "Tomorrow is going to be a must-win until ... until ... until ... we win it or lose it."
San Francisco is five games back of San Diego in the NL West and 4½ games behind Los Angeles in the wild-card race with 12 games remaining. The Giants have lost six of their last eight, including a 20-8 rout against the Rockies on Monday night.
"It was good old-fashioned hardball out there," Clint Hurdle said.
Cain, who had given up one earned run in his prior 42 innings coming in, didn't have his best command Tuesday. The rookie allowed seven runs and 11 hits in 5 1/3 innings.
"If you get behind in this place, it's going to hurt you," he said.
Garrett Atkins did much of the damage to the Giants with a pair of home runs, a triple and a single. Atkins drove in four runs and has 10 RBI in his last two games. He combined with Holliday to give Colorado back-to-back homers for the fourth time this year.
"I'm just trying to hit the ball hard and hit line drives," Atkins said.
Holliday's homer to left in the third traveled 478 feet, the longest at Coors this season. With an RBI double in the sixth, Holliday reached 100 RBI for the first time.
"Its a milestone, but its also a sign of how the team is, because I couldn't get 100 RBI without the guys being on base," Holliday said.
Barry Bonds' run-scoring single in the third gave him 1,922 RBI, tying Jimmie Foxx for fifth place. Bonds was 2-for-4 with a walk, but hit an inning-ending flyout with the bases loaded in the eighth off Jeremy Affeldt, who picked up his first save since Sept. 22, 2004.
Jason Jennings (9-12), who entered with the lowest run support in the NL (4.01), allowed three runs and seven hits in five innings. Colorado had 17 hits, raising its two-game total to 36.
After Atkins' homer in the eighth, Wright hit Holliday in the back with a pitch. Holliday threw his bat down and walked to first, and Reed ejected Wright. Alou said he went out to "reason" with Reed, and was ejected for the second time this season -- both at Colorado.
"Either Clint or I was going to go in that game, and I decided it was going to be me," Alou said.
The Giants took exception after Jose Mesa hit Mark Sweeney in the top of the eighth and nothing was said.
"Jose Mesa can hit a guy every single time he plays us," Wright said. "That one just ran in a little too far."
Colorado took a 2-0 lead on Todd Helton's sacrifice fly in the first -- ending Cain's scoreless streak at 18 1/3 innings -- and Kaz Matsui's run-scoring single in the second.
Bonds' single in the third cut the lead in half, but the third-inning homers made it 4-1. San Francisco closed within a run in the fifth when Steve Finley scored on a wild pitch following his leadoff triple and Ray Durham had an RBI single.
Atkins hit a two-run triple in the sixth that chased Cain, and Holliday greeted Kevin Correia with an RBI double, then scored on Helton's single to make it 8-3. Omar Vizquel singled in a run in the eighth.
Atkins had his first multihomer game. ... The Rockies are planning a tribute to INF Vinny Castilla on Sunday. There will be video highlights of his career and he'll start at third base. ... Matsui went 2-for-5 and had two steals. ... Pedro Feliz was 2-for-5, extending his hitting streak to 10 games. ... Finley was a homer short of the cycle.