DENVER — A punchless offense has coincided with the San Francisco Giants' seven-game losing streak.
Nolan Arenado and Carlos Gonzalez hit back-to-back homers in the first inning, and the Giants couldn't respond against the sharp pitching of Jorge De La Rosa in a 2-1 loss to the Colorado Rockies on Friday night.
San Francisco has averaged only 2.1 runs during its losing streak, the third one this season of at least seven games. Midway through a crucial 10-game road trip, the Giants are 0-5.
"It's a tough stretch, no doubt about it," Giants catcher Buster Posey said. "Be lying if you said it wasn't. We've got to find a way to turn it around though. It's all you really can do. You can't feel sorry for yourself, you can't pout. You just have to come ready to play and hope tomorrow is the day that we get back on track."
De La Rosa (9-6) didn't walk a batter and struck out seven. Two of the strikeouts came in the sixth inning, helping him get out of a jam and he induced an inning-ending double play grounder from Juan Perez after giving up a one-out single to Kelby Tomlinson in the seventh.
John Axford worked a scoreless ninth for his 19th save.
Rookie Chris Heston (11-9) went 5 2-3 innings for the Giants and allowed seven hits and two runs, both on the solo homers in the first.
"The kid did a great job after giving up two home runs in the first," manager Bruce Bochy said. "He got us deep in the game and pitched well. Two runs here in this park from a starter you take that, the bats are just quiet. We're having a hard time generating some offense. We did hit the ball hard. Boys could use a break."
Gonzalez hit a towering drive in the first inning that narrowly sailed foul. He hammered the next offering from Heston over the wall in center field for his 36th home run of the season, extending a career high. Arenado followed by connecting for his 35th of the season, joining Dante Bichette (1995) and Larry Walker (1999) as the only Rockies to homer in five straight games.
It was the second time this season that Gonzalez and Arenado teamed to go deep in successive at-bats.
San Francisco pulled to 2-1 in the sixth on a one-out RBI single by Angel Pagan. Matt Duffy singled and Buster Posey was hit by a pitch around a strikeout by Brandon Belt to load the bases. But De La Rosa escaped further damage by striking out Marlon Byrd.
Giants: SS Brandon Crawford played for the first time in four games. He missed the previous three games because of a calf injury suffered Monday when he was hit by a pitch in a game against the Los Angeles Dodgers. ... INF Joe Panik has begun a rehab assignment with Triple-A Sacramento. He has missed the last 32 games with a back injury.
Rockies: Utility player Matt McBride was designated for assignment to clear a spot on the 40-man roster for Justin Morneau, who was activated Friday after missing nearly four months because of a concussion. He singled in his first at-bat and finished 1 for 4.
Giants: RHP Jake Peavy (4-6) faces Colorado for the first time this season. He's 5-7 with a 3.95 ERA in 20 previous starts against the Rockies.
Rockies: RHP Chad Bettis (6-4) is 1-0 with a 4.09 ERA in two starts since returning from a six-week stint on the DL due to inflammation in his pitching elbow.