Kirby carved his way through the D-backs for a career-high 12 strikeouts over seven scoreless innings on Saturday night at T-Mobile Park, lifting the Mariners to a 3-1 victory to clinch their fourth straight winning series.

Six days after Kirby felt minor arm soreness and departed after five scoreless innings and 88 pitches at Coors Field, he was in peak form – and not just in the box score. Kirby came out firing his four-seam fastball harder than he has all season, generating seven whiffs among the eight total swings in the first inning, when he struck out the side exclusively on heaters.

From there, he was off and running. Kirby topped out at 99.3 mph, his fastest pitch of the year and strike three to Lourdes Gurriel Jr., and sat at 96.4 mph on the four-seamer, a healthy 1.2 mph uptick from his season average.

Velocity and whiffs have always been part of Kirby’s game, but never like this. And though the game plan with catcher Cal Raleigh called for a heavy dose of heaters, they doubled down once they realized what they were working with.