PHOENIX — The Rockies’ amazing metamorphosis continued Monday night in the desert.

Combining a superb start by lefty Christian Friedrich with some potent early offense, the Rockies blanked the Diamondbacks 4-0 at Chase Field.

It was the Colorado’s seventh victory in its last eight games.

Turning point. Friedrich’s moment of truth came early.

The Diamondbacks loaded the bases in the first inning, wrapping two walks around a double by Paul Goldschmidt. Disaster seemed to be breathing on Friedrich’s neck, but he got Jason Kubel to fly out to center fielder Dexter Fowler, ending the threat.

Earlier in the inning, Fowler saved a possible run with a sliding catch of Aaron Hill’s sinking line drive.

On the mound. Friedrich started slowly, then got better as the game went along. Setting up Arizona hitters with a lively fastball, then freezing them with his curve and changeup, he pitched seven shutout innings, allowing four hits and striking out four. The only two walks he issued came in the first.

“That first inning, I didn’t have a feel for the fastball,” Friedrich said. “It wasn’t coming out of my hand right. The two-seamer was cutting and the four-seamer was running like a two-seamer. But as the game went on I was able to start mixing my fastball and curveball more.”

Reliever Matt Belisle gave up a double and a walk in the eighth, but struck out the dangerous Goldschmidt to kill the would-be rally.

Adam Ottavino gave up a single in the ninth but was never in danger.

Rockies roughed up Arizona lefty Joe Saunders. He was 5-1 with a 3.32 ERA against Colorado coming in, but exited after 6 innings, tagged for four runs (three earned) on 11 hits.

At the plate. Veteran first baseman Todd Helton joined Hall of Fame company with his leadoff double in the Rockies’ two-run second. It was extra-base hit No. 952 for Helton, tying him with Mickey Mantle for 47th on the all-time list.

Jordan Pacheco drove in Helton with an opposite-field single to right and eventually scored on a passed ball as the Rockies went ahead 3-0.

“Pacheco gave us another good at-bat and he’s just getting better and better defensively at third base,” manager Jim Tracy said.

Rookie catcher Wilin Rosario crushed his ninth homer of the season in the fourth, putting the Rockies in front 4-0. The shot to right-center came about 15 feet from splashing down in the Chase Field swimming pool.

Rosario’s nine homers lead all major-league rookies.

Fowler continued to stoke the offense, leading off the game with his sixth triple and scoring on Marco Scutaro’s sacrifice fly. It extended Fowler’s hitting streak to a career-high nine games.

What it means. The Rockies’ slogan is “Swag,” short for swagger. It seemed a little premature when it first caught on during their last homestand, but the Rockies are playing solid baseball in all facets of the game right now.

“This was just a good game for us — really, really good,” Tracy said. “The competitiveness of our starting pitching has improved immensely over the last two days.”