SEATTLE -- In the context of the opponent, the beleaguered state of the rotation and where he stands in his continued development, Justus Sheffield’s outing in Sunday’s 2-0 win over the Angels ranks among the very best of his young career.

The 24-year-old threw six shutout innings, struck out four, gave up just two hits, walked three and hit two batters. He had decent stuff, but not his best. Yet the takeaways from this outing were that Sheffield worked out of jam after jam, capped by a punchout that sent Albert Pujols’ bat sailing down the third-base line to punctuate his career-high 103-pitch day.

"We had him first and third a couple times early with the right guys coming up,” Angels manager Joe Maddon said. “It just did not want to happen. And Sheffield was making better pitches, game-in-progress. He was very good."

Sheffield gave a banged-up Mariners rotation what they sorely needed: length, conviction and reassurance. For at least the afternoon, he spelled the club’s uncertainty with what to do with Marco Gonzales’ rotation spot on Monday, as well as a taxed bullpen that had thrown 12 innings over the first two games of the series.

Speaking of, that lock-down 'pen was again stellar in the series finale, with each of its highest-leverage arms -- Will Vest, Anthony Misiewicz, Kendall Graveman and Rafael Montero -- pushing the Mariners through the final three scoreless innings.

It was the Angels’ first shutout of the season, and it didn’t look like it was going to shape up that way early, with Sheffield putting runners on the corners in each of the first three innings against a hungry -- and loaded -- lineup. Yet his defense helped him out of each of those sequences via a groundout, lineout and double play.

Then in the sixth, Sheffield won an impressive nine-pitch battle against Anthony Rendon by striking out the star third baseman looking with a pitch on the lower black. He generated a sky-high popup to Justin Upton that ended an eight-pitch at-bat. And he capped it by fanning Pujols to end his outing.

“Today, I felt like, even with runners on, I feel like I didn't get really quick,” Sheffield said. “I stayed within myself. I stayed in control, I felt I was able to make some pitches when I needed to. And that's pretty much what this game boiled down to, was making pitches when I really needed it."

Just as encouraging as it was for the uncertain Seattle rotation in this early leg of the season, it was huge in the context of Sheffield’s maturation. As the Mariners’ pitching staff migrates its younger starters into their next stage of career development -- throw Justin Dunn in this category, too -- the leash will continue to grow, but so will the expectations.

Sheffield followed up his stellar rookie 2020 with a mixed first month in ‘21. Sunday marked his fifth start, and four of those have been against lineups that rank among the seven best in offensive WAR, per FanGraphs: the White Sox, Dodgers and Astros, in addition to the Angels. And he entered the day with a 5.32 ERA and a 75 ERA+ (where league average is 100).

What was telling about Sunday, though, was that Sheffield meandered his way through without his best stuff -- though he regained the command of his elite slider after a career-high 12-hit outing his last time out in Houston.

“Real scattery, I would say of my command,” Sheffield said. “Definitely not the best. Especially after the past three games, I felt like my command was pretty decent. But it's funny how the game works. To walk out of here with six innings, no runs and didn't have the best command -- at the end of the day, I’ll take it.”

His outing positioned the bullpen to take the reins in a two-run game that, given the Halos’ potential, never had the feel of finality until the last out.

Graveman’s ascent into the conversation as one the very best relievers in the American League had another big benchmark when he was called upon to face Mike Trout, Rendon and Jared Walsh in the eighth inning. He beat Trout by generating a weak infield putout on a 98.9 mph sinker with inside run, then Rendon got the best of him by singling in a nine-pitch at-bat, but he induced a 6-5-3 double play against Walsh to stall any rally.

“I saw that the game might be headed away, like in the sixth inning, doing the math looking at the lineup. … It’s really big in those moments, to get the leadoff guy no matter who it is, but especially when you're facing those three,” Graveman said.

And Graveman’s effort followed Misiewicz, who contributed just one -- but very critical -- pitch to Shohei Ohtani that led to an inning-ending groundout in the seventh. The Mariners’ bullpen lowered their MLB-best ERA to 2.30. Montero, who has blown four leads this season, also had a rebound with a 1-2-3 ninth inning.

“Last month, we put up some good numbers, but it's a new month and we kind of take it that way,” Graveman said. “We’re one-sixth of the way through as far as months, and [we'll] see if we can continue this trend going into this month and just break it down monthly.”