DENVER -- The Rockies and right-hander Rodrigo Lopez once again faced a painful result against the Dodgers and Brad Penny -- who hurt a little, himself -- on Thursday night.

Penny won for the 12th time in 14 decisions against the Rockies, 5-4, at Coors Field in front of 31,057, on the strength of a costly two-run error by center fielder Willy Taveras in the fourth inning and a two-run homer by the Dodgers' Rafael Furcal in the fifth.

Lopez (5-4), who left after 6 2/3 innings with tightness in his right forearm, allowed five runs (three earned) on five hits. But Lopez said it wasn't the same injury he suffered while facing the Dodgers on April 16, when the injury was more in the elbow area and forced him to the disabled list for more than a month.

Penny (13-1) left after suffering an abdominal cramp while beating out an infield roller in the seventh. He held the Rockies to five hits and three runs and struck out five in six frames.

The National League West-leading Dodgers took the opener of a four-game set with the Rockies, who now trail them by 5 1/2 games. The Rockies, who are still 16-5 at Coors since June 2, got three RBIs from Brad Hawpe and nearly erased a 5-0 deficit.

"We kept fighting back," Rockies manager Clint Hurdle said. "We just didn't get enough to get on top."

The Dodgers took a 3-0 lead in the fourth inning. Two runs scored when Taveras became twisted on Luis Gonzalez's one-out fly ball and lost the ball when he bumped into the fence. Nomar Garciaparra added a two-run single in the inning.

"I think the wind got that ball a little bit, and that's where I got confused right there, but I could've made that play," Taveras said.

Without the error, Lopez might have been good enough. Lopez, who is 0-2 in his last two starts despite a respectable 3.20 ERA, wanted to stay in the game after striking out Matt Kemp swinging in the seventh. But with Hurdle and head trainer Keith Dugger on the mound, catcher Yorvit Torrealba ended any debate by pulling the ball from Lopez's hand.

Thursday's loss dropped Lopez to 5-1 at Coors, and it was the Rockies' first loss in his eight home starts.

"It was stiff through the game, but at the end, I didn't have any more strength and wasn't able to execute pitches," said Lopez, who said he hopes to make his next start and believed Monday's off-day will give him time to get healthy. "There's soreness right now in the muscles in my forearm, and we'll see how it goes.

"Things happened in the fourth inning. I think I made my pitches but didn't have the result that I wanted. I think the only bad pitch that I made was to Furcal. I was trying to go down and away, and the ball stayed middle-away."

The Rockies responded to the Furcal homer, his fourth of the season, with three runs against Penny in the sixth on Todd Helton's sacrifice fly and Hawpe's bases-loaded, two-run single. It gave Hawpe an NL-leading 45 RBIs with two outs.

Hawpe added an RBI single in the eighth off Jonathan Broxton, but the Rockies didn't score again. Takashi Saito, who had not pitched since July 18 because of tightness in his right shoulder blade, earned his 26th save by overcoming a two-out walk and striking out Matt Holliday.