Logan Webb wasn’t quite as untouchable as he was during Spring Training, but he delivered a solid performance in his 2021 debut on Saturday night. The same couldn’t be said for the Giants’ bats, as they were shut out, 4-0, to drop their first series of the regular season against the Mariners at T-Mobile Park.

Webb struck out five and allowed three runs on seven hits and three walks over 5 1/3 innings, but he was charged with the loss as San Francisco mustered only six hits. The Giants scored 13 runs over their first two games of the season, but they were stymied by Chris Flexen -- the first right-handed starter they faced this year -- who struck out six over five scoreless innings.

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“He kept us in the baseball game,” manager Gabe Kapler said of Webb. “We didn't swing the bats enough to support the work that he did, but he was efficient and he enabled us to kind of be in the game through the end of his start. I thought it was a mature outing for him.”

Webb enjoyed perhaps the best camp of any Giants player this spring, logging a 0.53 ERA with 22 strikeouts over 17 innings in five Cactus League starts to secure his spot in the starting rotation. The 24-year-old right-hander worked around early traffic on Saturday and made only one mistake through the first three innings, misplacing a changeup that Ty France drove to left-center field for a solo homer in the third.

The Giants believe Webb’s changeup has the potential to be an elite secondary weapon, but he had a harder time fooling the Mariners with that offering in the fourth. Seattle’s batters appeared to be hunting the offspeed pitch, as Evan White, Taylor Trammell and Dylan Moore opened the inning with three consecutive doubles -- each of which came on two-strike changeups -- to extend the Mariners’ lead to 3-0.

“I feel like most teams are probably going to be looking for that pitch,” Webb said. “I’ve just got to execute better. Those three straight doubles -- the Trammell one wasn’t too bad, but the other ones, I can’t leave them that far up. When you get two strikes and you leave a pitch kind of middle-middle, it’s frustrating. It’s something I’ll work on.”

Thirty-five of Webb’s 97 pitches were changeups, the third most he’s thrown in any of his 22 career big league appearances. Despite the results in the fourth, Webb said his confidence in that pitch hasn’t wavered and he intends to continue to lean on it in future outings.

“I’m going to keep throwing it,” Webb said. “Now it just comes down to executing that pitch. I feel like I do have pretty good control of that pitch right now, I think I just got a little too happy with it. The second time through the lineup, maybe I’ll mix in a different pitch. But it doesn’t necessarily shake my confidence in that pitch. I’m going to keep throwing it, and I’m excited to keep throwing it.”

Webb has a 5.35 ERA over his first two seasons in the Majors, and he finished the 2020 campaign in the bullpen, but the Giants believe he has the potential to develop into a quality big league starter. Webb’s progress will be an important storyline for San Francisco in 2021, as it is trying to find long-term answers for its starting rotation, which currently features five veterans -- Kevin Gausman, Johnny Cueto, Anthony DeSclafani, Aaron Sanchez and Alex Wood -- who will be eligible for free agency at the end of the season.

While Webb couldn't sustain the dominance he enjoyed during the spring, Kapler said he thought the outing still marked an important step forward for Webb.

“I think the final line looked pretty similar to several of the lines that we saw last year from Webby, but I thought it was different in that he continued to attack the strike zone,” Kapler said. “He certainly got a good feel for that changeup and even made some adjustments with the changeup after we saw some of the hard contact.

“By introducing and getting a feel for a new pitch, or introducing different pitch usages, we don't guarantee that there's not going to be hard contact. We can expect hitters to make adjustments, but what's important is that as he continues to develop this really unique weapon, he's ultimately going to grow into being able to throw it in and out of the zone. But right now, he did exactly what we asked him to do.”