SAN FRANCISCO -- After his rough start against the Dodgers last week, Drew Pomeranz said he felt he had identified the issue and pledged to work on correcting the flaw in his next bullpen session.

“I think that I know what I was doing wrong,” Pomeranz said. “I think this should be an easy fix for me.”

• Box score

In between starts, Pomeranz worked on becoming more comfortable with a new arm slot that helped spur a turnaround by helping him stay more on top of the ball. He returned to form Monday night, matching his career high by striking out 11 over five innings, but he was charged with the loss after the Giants were shut out, 2-0, in their series opener against the Rockies at Oracle Park.

Pomeranz allowed only a two-run home run to David Dahl in the 93-pitch effort, but it proved to be the difference in the game, as Colorado right-hander Jon Gray held the Giants to four hits over six scoreless innings. Pomeranz became the first Giants starter to reach double-digits in strikeouts since Johnny Cueto on April 17, 2018, against the D-backs.

“I think the last start I had, it was kind of just forcing it a little bit,” Pomeranz said. “Today I just kind of went out there and just simplified my approach. My fastball stays a little truer and goes where it’s supposed to instead of running back over. It helps my curveball. I think it just helps everything. It just helps me be in the strike zone a little more, even though I walked a couple guys. I still feel like, for the most part, I was throwing stuff where I wanted to.”

After posting an 8.08 ERA over his first 10 starts, Pomeranz decided to raise his arm slot, an adjustment that helped spark an encouraging resurgence. Over his next two outings, Pomeranz allowed no earned runs over 10 innings, though he experienced a setback after yielding seven runs over 4 1/3 innings against the Dodgers on Wednesday.

Still, Pomeranz managed to regain his sharpness against the Rockies, striking out five of the first seven batters he faced.

"Good fastball,” Rockies manager Bud Black said. “We might have been looking a little bit for the curve early in the game, and he started getting some fastballs by us. It looked like, from my vantage point, that his fastball had a little bit more carry, a little bit more life to it, maybe a little bit better location, than he's shown in his last few starts.”

The lone blemish against Pomeranz came in the third, when Charlie Blackmon blooped a single into left field and Dahl launched a first-pitch fastball out to left field to give the Rockies a 2-0 lead.

“I was trying to go in on him, and instead of staying in, it cut back to the middle of the plate,” Pomeranz said. “That’s the one pitch I’ll probably think about the rest of the night. That’s baseball. It happens. Sometimes one pitch decides the game.”

Pomeranz breezed through the fifth, striking out Dahl and Nolan Arenado and coaxing a flyout from Daniel Murphy to cap his night. He spotted a 90.2-mph fastball on the outside corner for a called third strike against Arenado, who became Pomeranz’s 11th and final strikeout victim. The 11 strikeouts were the most for Pomeranz since May 25, 2017. Nine of his strikeouts came on his fastball.

With the Giants in need of a run, manager Bruce Bochy opted to have Brandon Belt pinch-hit for Pomeranz with a runner in scoring position and one out in the bottom of the fifth. Belt drew a walk, but Gray struck out Mike Yastrzemski and Alex Dickerson swinging to escape the jam.

“He had good stuff,” Bochy said. “Eleven strikeouts there, but we were down, so I was kind of forced to hit for him with a runner in scoring position, or else he could have gone out there and given us at least another inning. He did a good job of bouncing back. He pitched a nice ballgame. Tough game for him not to get a win, the way he was throwing the ball.”

The Giants threatened again in the seventh after Joe Panik singled and attempted to score from first on Yastrzemski’s two-out double to the left-center-field gap. Waved home by third-base coach Ron Wotus, Panik was subsequently tagged out by catcher Tony Wolters, who had to collect a slightly off-line throw from shortstop Pat Valaika before recording the out.

The Giants challenged the call, but the ruling was upheld following a replay review. They finished 0-for-5 with runners in scoring position, sealing their ninth shutout loss of the season.

“You could tell it was close,” Bochy said. “The ball beat him, but the tag, whether it got there in time, it was hard to tell.”