The Mariners’ starting rotation will fly back to Seattle having taken a major stride forward.

Marco Gonzales and Justin Dunn spun together sensational outings as the Mariners swept Thursday’s doubleheader against the Orioles, combining to allow three earned runs across 10-plus innings with 11 strikeouts.

“It was really outstanding pitching all day today,” said manager Scott Servais.

Dunn found the strike zone as the Mariners beat the Orioles, 2-1, in the second game of the doubleheader, allowing just one run in 5-plus innings with six strikeouts and two walks.

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For Dunn, the effort was quite the rebound after he yielded a career-high eight walks to the White Sox in his first outing of the season.

“Nice bounce-back outing for Justin Dunn,” Servais said. “Struggled [with] command in the strike zone last time out. Today, you could see that his full focus was on getting ahead in the count, getting right after them.”

The right-hander’s stellar outing came on the heels of Gonzales’ equally encouraging performance in the first game of the doubleheader, which the Mariners won, 4-2. Seattle’s ace bounced back from a shaky first inning, allowing just two earned runs across five innings and striking out five.

The biggest mark of Dunn’s growth between starts came in the bottom of the fourth. After plunking Trey Mancini to begin the frame, Dunn struck out the side with three perfectly placed sliders, all of which began in the zone before sharply ducking out as they crossed the plate.

As encouraging as the strikeouts was the fact that they came out of the stretch. Dunn said after his season-opening start against the White Sox that he had trouble getting comfortable pitching with runners on base. On Thursday, he found that groove, retiring all six batters he faced out of the stretch.

Dunn said that his ability to consistently hit the strike zone was less about mechanics and more about mentality. Instead of nibbling around the corners as he did against the White Sox, Dunn said he was more willing to challenge hitters and live with the results. The numbers back up that approach as Dunn threw first-pitch strikes to 15 of the 20 batters he faced.

“Everything today was, ‘Here it is, hit it' -- 0-0, 0-1, I was going to give you one to hit, get ahead, and let myself play," Dunn said. "I knew if I could get ahead and expand later, I’d have some success.”

Dunn, who had several family members in attendance, also reflected on the significance of being able to pitch on Jackie Robinson Day. Along with donning No. 42 like every ballplayer, Dunn donned a pair of all-black, Robinson-inspired Ken Griffey Jr. cleats.

“I wouldn’t be here without him,” Dunn said.

The rotation’s performance against the Orioles was refreshing after the unit badly struggled to begin the season. Seattle’s starters came into this series with a combined 6.23 ERA, the second-worst mark in the Majors.

Through the efforts of Gonzales, Dunn and Justus Sheffield, who threw six innings of two-run ball in the series opener, the starters have gotten their collective ERA down to 5.36, nearly chopping off a full run. There’s still room to improve, but the starters are trending in the right direction.

Upon returning to Seattle, the Mariners’ starters will have the challenge of neutralizing the Astros and Dodgers, two of the league’s most potent lineups, across their next five games. Entering Thursday, Los Angeles and Houston had the first and second-best wRC+, respectively.

Houston will likely be without Yordan Alvarez, Alex Bregman and Jose Altuve, all of whom were all placed on the injured list.