It all started with Heaney getting into a bit of a jam, thanks in part to his defense. He allowed a walk and a single (with a strikeout in between, which will soon be a theme) before a fielding error put the Royals on the board. Heaney was already down 1-0 and dealt with runners on second and third with just one out.
He would then strike out the next two hitters to end the inning. In the second inning, Heaney struck out all three hitters he faced. In the third inning, he again struck out all three hitters he faced. Leading off the fourth inning was Royals catcher Salvador Perez, and he struck out.
That was nine straight strikeouts, which was his 10th strikeout in 10 outs.
The nine straight strikeouts broke the Rangers record, formerly seven, which was held by a guy named Nolan Ryan (ever heard of him?).
The nine consecutive strikeouts also tied the American League record and fell one short of tying the MLB record. Here are the pitchers who have managed at least nine straight strikeouts in a game.
9 - Andrew Heaney (April 10, 2023), Pablo López (July 11, 2021), Jacob deGrom (April 17, 2021), Tyler Alexander (Aug. 2, 2020), Max Scherzer (Oct. 3, 2015), Doug Fister (Sept. 27, 2012), Aaron Harang (April 13, 2012), Ricky Nolasco (Sept. 30, 2009), Jake Peavy (April 25, 2007), Mickey Welch (Aug. 28, 1884)
Aside from Heaney, the only AL pitchers on that list are Alexander and Fister.