Cole Irvin’s outing didn’t end on the strongest note, but his latest performance can be categorized as yet another net positive.

Irvin strung together another encouraging start as the A’s extended their win streak to 12 games with a 3-1 win over the Orioles, holding the Orioles to one earned run across 5 1/3 innings with six strikeouts and one walk.

“He’s been really impressive this year,” said manager Bob Melvin. “You look up, and he’s got a sub-four ERA? He’s done well.”  

Partial credit of Irvin’s final line should be credited to Yusmeiro Petit. As good as Irvin’s start appears just by looking at the numbers, the southpaw’s final line may have looked a lot different if not for the mid-game heroics of Petit.

• Petit’s command keys bullpen's success

Irvin cruised for the better part of five innings, occasionally working out of minor turbulence, but allowed three straight singles to begin the sixth inning. Melvin wanted to give Irvin a shot to get out of trouble, but after Pedro Severino’s loud, one-out RBI single, Irvin was pulled for Petit with the game hanging in the balance.

The veteran was thrown into a bases-loaded, one-out situation with the A’s clinging to a two-run lead, but dispensed of the next two batters without any drama. Petit got Freddy Galvis to pop out on one pitch, then needed just two more to get Ramón Urías to ground into a forceout and quell the danger. 

Petit pitched another scoreless inning for good measure before handing the ball off to J.B. Wendelken and Jake Diekman, who subsequently locked in Oakland’s latest win.

“Key to the game,” Melvin said of Petit. “We’ve seen him do it -- I don’t know how many times. It’s not an easy thing to do.”

Irvin’s rough sixth inning slightly soured his outing, but the lefty kept Baltimore’s bats in check through the first five frames. While Irvin couldn’t finish the sixth inning, he escaped the first and fourth innings unscathed after putting runners on base. At one point, Irvin retired 10 consecutive batters.

The southpaw’s bread and butter against Baltimore was his changeup, which generated a career-high 10 whiffs. Irvin was willing to throw his changeup regardless of count -- in the first inning, Irvin threw back-to-back changeups to Maikel Franco on a 3-0 count, generating a pair of swinging strikes.

“Changeup was definitely the go-to pitch today,” Irvin said. “Could throw that [on] any count. Just was one of those days where [my] sinker, changeup, four-seam were just all working.”

Irvin’s and the bullpen’s great overall performance was needed on a night when the A’s offense was generally quiet. The A’s had a few offensive highlights -- Ramón Laureano had a no-doubter home run, while Matt Olson and Stephen Piscotty had two-hit nights -- but was actually out-hit by the Orioles. Jorge López essentially gifted the A’s a pair of runs, walking two batters then throwing a wild pitch to set up Oakland’s two-run second inning.

Yet, as has been the theme as of late, the A’s are finding ways to win, however they may come. 

“Tonight, we didn’t have a ton of offense, but Irvin did a tremendous job shutting it down,” Piscotty said. “Same with Petit coming in in a big spot. That’s a great sign when you’re getting great performances. The offense is picking up the defense, and the defense picking up the offense.”

Given how well Irvin has pitched to begin the season -- he now owns a 3.86 ERA in 21 innings -- the A’s have a tough decision on their hands. Irvin has been filling in for starter Mike Fiers, who is expected to make his season debut in the coming days. Fiers is a deserving incumbent of the starting rotation, but Irvin continues to impress with every subsequent outing, particularly in his ability to navigate with runners on base. 

“We didn’t know a ton about him coming into spring,” Melvin said. “Battled for that job, won it at the end, and keeps going out there and giving us reasons to run him back out there.”