Jacob Misiorowski opened the World Series with a 103.5 mph fastball, the hardest pitch tracked in Fall Classic history, and threw 10 pitches at 101 mph or faster in the first inning of Game 1 on Friday night, out of 13 pitches total in his debut inning.
The Milwaukee Brewers right-hander fired that first pitch to Tampa Bay Rays leadoff man Yandy Díaz at American Family Field. He threw 11 fastballs in the inning, averaging 101.9 mph, according to pitch tracker x9Lab.
Aroldis Chapman held the previous World Series record at 103.2 mph, set in 2016. Among starters, Noah Syndergaard topped the tracking-era list at 101.1 mph in 2015, according to MLB.com reporter David Adler.
Two singles put runners aboard before Junior Caminero’s lineout became a double play that ended the half-inning, according to Yahoo Sports reporter Jack Baer. The Rays did not score.
Jacob Misiorowski’s World Series Pitch Breakdown
The opener set the tone at 103.5 mph. Eleven pitches in the inning were fastballs, and they averaged 101.9 mph. No Game 1 starter since 2008 had averaged more than 98.2 mph to open an inning, x9Lab noted. Tyler Glasnow held that mark for the Rays in 2020.
Misiorowski opened NLDS Game 1 against the San Diego Padres with a 104.8 mph pitch, the fastest postseason pitch of the tracking era, according to MLB.com reporter Adam McCalvy. That inning took 25 pitches, and he left after 88 pitches in four innings.
He entered the World Series having failed to finish five innings in either start. His fastball averaged 100.6 mph in the regular season and 101.0 mph in the postseason, but the pitch’s swing-and-miss rate fell from 40.2 percent to 16.1 percent, according to CBS Sports.
“I’ve just got to stick to my strengths and pound the zone,” Misiorowski said Thursday, as quoted by CBS Sports.
Jacob Misiorowski’s Career, Bio and Background
Jacob Walter Misiorowski, nicknamed The Miz, was born April 3, 2002, in Blue Springs, Missouri. He stands 6-foot-7 and weighs 201 pounds.
He went undrafted out of Grain Valley High School, then enrolled at Crowder College and first touched 100 mph at the 2022 Junior College World Series, according to Sports Illustrated writer Tom Verducci. The Milwaukee Brewers drafted him in the second round that year, and he agreed to terms at $2.35 million.
He debuted June 12, 2025, against the St. Louis Cardinals, allowing no hits over five innings, and reached the All-Star Game as a rookie. His 2025 line came in at 5-3 with a 4.36 ERA and 87 strikeouts in 66 innings.
He led the majors in ERA, strikeouts and WHIP in 2026, going 16-5 with a 1.80 ERA, 252 strikeouts in 174 2/3 innings and a 0.802 WHIP. Opponents hit .157 against him. His career line stands at 21-8 with a 2.51 ERA and 339 strikeouts in 240 2/3 innings.
Misiorowski topped out at 105.5 mph this season, and Adler reported he has thrown 1,211 fastballs in triple digits, topping Chapman’s 2016 total of 723 by 488.
“It’s like he was built in a lab,” Brewers starter Brandon Woodruff said, as quoted by Sports Illustrated. Misiorowski gained close to 30 pounds over the winter, mostly in his legs, Verducci reported.
Milwaukee entered the World Series 7-1 in the postseason after sweeping the Los Angeles Dodgers in the NLCS, according to Yahoo Sports.
What Did Jacob Misiorowski Just Do in His First World Series Inning?