Vladimir Guerrero Jr. led off an explosive seventh inning with a single off rookie left-hander Keegan Akin (2-9), and Bo Bichette followed with a towering homer to left field. Tanner Scott entered for Baltimore and gave up another two-run homer to Alejandro Kirk before Marcus Semien and Teoscar Hernandez added three-run shots.
Toronto ultimately tied team records for an inning with 11 runs, 11 hits and four homers. They became the first team to win by nine or more runs after going hitless through six innings since 1997.
The Blue Jays also put up 11 runs in the first half of the doubleheader, an 11-10 victory.
"I don't believe what I just saw," Toronto manager Charlie Montoyo said. "Honestly, what we did in the first game, I [wasn't] expecting in the second game. There's no way. That's what this team does. We didn't quit."
Information from The Associated Press was used in this report.