Burnes' record-tying strikeout came in the bottom of the fifth inning, when Cubs first baseman Frank Schwindel whiffed on an 88-mph slider. Third baseman Matt Duffy broke the string on the next pitch by singling to right field on a first-pitch fastball.
All 10 of Burnes' strikeouts came on swinging third strikes. The 26-year-old right-hander fanned the side in the second, third and fourth innings to set a Brewers team record at nine straight, before striking out Schwindel to lead off the fifth.
Burnes was in such a zone he didn't know he had tied the record.
"I had no idea. When I came in, Shawger said something," Burnes said, referring to Brewers equipment manager Jason Shawger. "I was like, 'What did I do? Why are we throwing the ball out of the game?' I had no clue."
The 10 strikeouts:
Schwindel: Swinging on a 0-2 slider.
Duffy: Swinging on a 0-2 curveball.
Greg Deichmann: Swinging on a 1-2 changeup.
David Bote: Swinging on a 1-2 slider.
Andrew Romine: Swinging on a 0-2 cutter.
Jake Arrieta: Swinging on a 1-2 curveball.
Rafael Ortega: Swinging on a 2-2 cutter.
Willson Contreras: Swinging on a 2-2 cutter.
Ian Happ: Swinging on a 2-2 cutter.
Schwindel: Swinging on a 0-2 slider.
Burnes shares the record with Philadelphia Phillies pitcher Aaron Nola, who pulled the feat against the New York Mets in June, and Hall of Famer Tom Seaver, who set the mark for the Mets against the San Diego Padres in 1970.
Burnes needed just 41 pitches to strike out the 10 hitters, with three of them going down on three pitches and none requiring more than five.
Burnes had a 7-0 lead before he even took the mound after the Brewers scored seven runs in the top of the first.
"It makes it really easy to just throw it over the plate," he said. "Even after scoring seven runs, they came out swinging, so after the first we said instead of leaving it over the middle let's just go back to our game plan and go to the edges and do what we do best. It worked. Credit goes to Omar [Narvaez]. I think I shook him off once all night."
Burnes finished the night with a career-high 15 strikeouts over eight scoreless innings, the second-most strikeouts in franchise history, behind Ben Sheets' 18 in 2004. The Brewers' director of team travel told Burnes that Sheets had texted him during the game, joking that he was getting nervous that Burnes was going to break his record.
"That's pretty cool he was watching it," Burnes said.
Burnes also matches Mets ace Jacob deGrom for most strikeouts in a game this season (both did it while allowing no walks), and his 30 swings-and-misses are the second-most in a game after the Angels' Patrick Sandoval recorded 32 in a June start against Seattle.
"Those first four innings were as good as anyone has pitched in a game -- not just this year, but in a long time," Brewers manager Craig Counsell said. "The swings were ... the swings just weren't good swings. It was a great pitcher at his best."
Burnes made strikeout history in April when he began the year with 58 strikeouts before issuing his first walk. That briefly stood as the all-time record for most strikeouts without a walk at any point in a season until Gerrit Cole broke it a few days later with 61.
It has been a remarkable turnaround for Burnes since 2019, when he finished with an 8.82 ERA. He improved to 7-4 with a 2.23 ERA and ranks third in the majors in ERA (teammates Brandon Woodruff and Freddy Peralta are second and fourth), third in strikeouts behind Zack Wheeler and Cole and first in strikeout rate at 36.1%. With just five home runs allowed in 121 innings, he also leads qualified starters in lowest home run rate.
The big change came in the 2019-20 offseason, when Burnes came up with a new cutter while tinkering with different grips for his slider. The cutter is now the pitch he throws most often, throwing it more than 50% of the time, helping to set up his deep arsenal of wipeout pitches. He threw it 53 times on Wednesday, out of 99 total pitches.