(SportsNetwork.com) - The San Francisco Giants aim to stay hot when they play a doubleheader Saturday against the Colorado Rockies at Coors Field.

The defending World Series champion Giants have ripped off seven wins in a row and improved to 15-5 this month with Friday's 11-8 victory over the Rockies in the opener of this four-game series.

Ryan Vogelsong threw six shutout innings for the win and received a healthy supply of run support. Brandon Belt and Matt Duffy both went deep and combined for six hits and four RBI. Buster Posey knocked in three runs for the Giants, who have scored nine or more runs four times during this win streak.

"That was a typical Coors Field ballgame," Giants manager Bruce Bochy said. "I've been in a few of them."

Chris Heston will take the mound for Bochy's club in the first game and is 3-3 with a 3.72 earned run average in eight starts. Heston lasted only two innings in Sunday's 9-8 win at Cincinnati and did not record a decision, touched for five runs and seven hits with two strikeouts and two walks.

Heston, who threw a two-hit, one-run gem on May 12 at Houston with 10 K's and no walks, has lost both of his starts against Colorado.

Yusmeiro Petit is slated for the nightcap and is 1-0 with a 3.27 ERA in 13 relief appearances this season. Petit has faced the Rockies 16 times (8 starts) in his career and is 3-1 with a 4.82 ERA.

The Rockies have lost four of their last six games and almost came back Friday with eight runs in the last three innings. DJ LeMahieu went 2-for-4 with a home run, three RBI and two runs scored, while Wilin Rosario recorded three hits and drove in a run.

"I've seen a lot of strange games here," said Rockies manager Walt Weiss. "The guys fought back late."

Kyle Kendrick was dealt the loss for giving up four runs in 6 1/3 innings.

Jordan Lyles will toe the rubber for the Rockies this afternoon and has a 2-4 mark with a 4.53 earned run average in eight starts. Lyles is winless (0-3) in his past four outings and permitted four runs in six innings of Monday's 4-3 loss to Philadelphia.

Lyles, who has allowed 14 runs in his past four appearances, has made four career starts against the Giants and is 1-1 with a 4.84 ERA.

David Hale will make his Colorado debut in the nightcap and was 4-5 with a 3.30 ERA in 45 games (6 starts) with Atlanta last season. He has faced San Francisco four times in relief, posting no record or ERA in 4 1/3 frames.

Colorado is 4-2 against San Francisco this season.