Struggling to throw strikes, Dodgers pitcher Chad Billingsley resorted to tossing the ball right down the middle. He didn't get past the third inning and by then, the damage was done.

Todd Helton and Troy Tulowitzki homered in leading the Colorado Rockies past Los Angeles 7-5 Wednesday for a two-game sweep.

Billingsley (1-1) took a 4-2 lead into the bottom of the third. But he fell behind in the count and Helton hit a 3-1 offering over the right-field wall for a three-run homer that put Colorado back in front.

"I just couldn't get ahead of hitters, and when you're not ahead of hitters, you have to come back over the plate," Billingsley said. "I was leaving stuff over the middle part of the plate."

The ball didn't stay there for long as Billingsley allowed five runs on six hits with three walks.

It was the latest in a series of tough outings against Colorado for Billingsley. He fell to 2-5 with a 5.40 ERA in 12 career appearances (10 starts) against the Rockies.

"He seemed to struggle with his stuff, throwing the ball where he wanted to," Dodgers manager Don Mattingly said. "Kind of frustrating. They get two early, but we get back in the game quick and then from there we let them right back, jump right back on us."

Tulowitzki went deep for the second straight day, sending Blake Hawksworth's offering into the left-field bleachers an inning later for a two-run shot that made it 7-4.

Jason Hammel (1-0) was the beneficiary of the pop in the middle of Colorado's lineup, picking up the win despite allowing two home runs in five innings and falling behind 4-2 in the third.

After Rockies lefty Franklin Morales pitched two scoreless innings of relief, Matt Lindstrom came on and allowed one run in the eighth when center fielder Dexter Fowler couldn't track down Matt Kemp's fly ball that went for a double. Kemp advanced on a groundout by James Loney and scored on Juan Uribe's groundout.

Huston Street pitched the ninth for his third save in three chances, but once again it wasn't without struggle.

The slow-footed Rod Barajas singled down the left-field line leading off and Jamey Carroll did the same, putting runners at first and second with nobody out. Rafael Furcal lined a fastball to left that looked like it was going for extra bases, but Carlos Gonzalez made a terrific over-the-shoulder catch, and because Barajas wasn't tagging, the runners stayed put.

Street then struck out pinch-hitter Hector Gimenez and Andre Ethier to end it.

Mattingly said he didn't seriously consider lifting Barajas for a pinch-runner.

"Not really there, not down by two," Mattingly said. "I don't feel like it does anything for us. He pretty much can't tag, you're still going to play that halfway. Jamie was the key guy, the guy at first who can run. If the ball's over his head, we have a chance to score both guys."

Furcal said he thought the ball would get over Gonzalez's head but he also was mindful that the Rockies left fielder was one of the few players in the league capable of making that catch.

"For me, that would have been a big hit because I've been struggling during this series," Furcal said. "Going into San Diego, we've got to forget about today. We lost already. We've got a day off and the next day we'll play. We've got to keep our heads up and try to play a little better."

Hammel was staked to a 2-0 lead in the first inning when Gonzalez doubled home a run and came around to score on Jose Lopez's single. But he surrendered Loney's solo homer in the third and Barajas' shot leading off the third, when the Dodgers took the lead.

Furcal walked and Casey Blake, who was activated from the 15-day disabled list before the game, tripled and scored on Ethier's single for a 4-2 lead.

NOTES: Earlier in the day, the Rockies placed ace Ubaldo Jimenez on the 15-day DL to give the cracked cuticle on his pitching thumb a chance to heal. RHP Greg Reynolds was called up by the Rockies to take Jimenez's roster spot and will start Saturday in Pittsburgh. ... Blake had gone on the DL after injuring his back March 12 during spring training. ... Rockies 3B Ian Stewart went 0 for 4 with two called third strikes. He's 0 for 9 on the season. ... Rockies C Chris Iannetta singled off the center field wall in the second. ... These NL West teams won't face each other again until a three-game series at Dodger Stadium beginning May 30.