Santiago Espinal had two hits and drove in three runs as the Blue Jays pounded out a season-high 19 hits, including seven in a seven-run fifth inning.
Manoah (8-1) has won three straight starts and four consecutive decisions. He pitched six scoreless innings to beat the Royals in his previous start on June 7 at Kansas City.
Toronto is 25-7 in Manoah’s 32 career starts. He’s 10-0 with a 1.99 ERA in 15 career home starts.
Guerrero led off the eighth with his 15th home run, a 432-foot drive off right-hander Rico Garcia.
A win at Kansas City on Sunday gave the Orioles back-to-back victories for the first time since May 22-23, but Baltimore never came close to winning three straight for the second time this season.
Manoah allowed one hit, Jorge Mateo‘s leadoff single in the third. He walked one and struck out seven.
Promoted from Triple-A Norfolk earlier Monday to make his major league debut, Orioles outfield prospect Kyle Stower drove in Baltimore’s run with an RBI double off Julian Merryweather in the seventh. The hit was the first of Stower’s career.
Orioles right-hander Kyle Bradish (1-4) allowed five runs and nine hits in 4 1/3 innings, extending his winless streak to six starts. He walked one and struck out three.
Baltimore challenged after Trey Mancini appeared to ground out weakly in the sixth. After a lengthy review, the umpires ruled that Mancini had been hit by Manoah’s two-strike pitch but did not hold up his swing, meaning he had struck out. It meant the Orioles won their challenge, but didn’t get a baserunner.
Guerrero had to grab a new glove from the dugout in the ninth after a throw from Espinal at third base tore the webbing of his first baseman’s mitt.
Blue Jays: Merryweather was replaced by Adam Cimber in the seventh after he felt discomfort in his left side. . 3B Matt Chapman (left wrist) took batting practice, but was held out of the lineup for the third straight game.
Baltimore added Stowers and Garcia as substitute players from Triple-A Norfolk and put OF Anthony Santander and LHP Keegan Akin on the restricted list. . INF Chris Owings cleared waivers and was released.