Monell, a 27-year-old journeyman catcher purchased from the San Francisco Giants this offseason, connected on a fastball from Twins setup man Jared Burton.
The Orioles also stole third base twice in the same inning off Burton, making his second appearance of the spring.
Baltimore scored five more runs in the sixth, when second-base prospect Jorge Polanco made a throwing error that led to four unearned runs off Twins left-hander Scott Diamond.
Orioles: Right-hander Chris Tillman, the likely opening-day starter, gave up four hits and three runs — one earned — in 2 1-3 innings but was encouraged by his outing.
"I've got no complaints," Tillman said. "Physically, it felt good. Mechanically, I felt good, too. I think pitch execution was good for the most part."
Twins: Right-hander Mike Pelfrey was surprised to learn he threw strikes on 66 percent of his 47 pitches in 2 1-3 innings.
"Really?" he said. "Well, there weren't enough quality strikes in there. I was all over the place."
Pelfrey took hard drive by Ryan Flaherty off the side of his right leg but stayed with the play to get the out. Pelfrey was disappointed with his "slow reactions" on that and one other ball hit back through the box.
Orioles: Outfielder David Lough was scratched from the lineup after being hit in the foot by a line drive on Wednesday morning in Sarasota. . Outfielder Henry Urrutia (sore right shoulder) has been cleared to play and is expected to return to the lineup on Thursday at home against Tampa Bay. . Infielder Alexi Casilla (hamstring) took batting practice and could return as soon as this weekend.
Twins: Shortstop Pedro Florimon (appendectomy) took grounders with the rest of the infielders and made light throws back to home plate. He is adding a little more to his work schedule each day. . Right-hander Matt Guerrier, coming off flexor-tendon surgery in August, threw batting practice for the first time on Tuesday. He is expected to face hitters again Friday before targeting a debut March 11 at Tampa Bay.
CHASING JOHAN: Assistant general manager Rob Antony acknowledged the Twins were outbid for their former ace and two-time Cy Young Award winner Johan Santana, who signed a minor league deal this week with the Orioles that guarantees him $3 million if he reaches the major leagues.
"He clearly got more money, I'll tell you that much," Antony said. "It's unique when you're dealing with somebody who has accomplished a lot in the game like he has, but you just go with what you feel is comfortable and make an offer."
The veteran left-hander, coming off his second shoulder surgery in a span of 31 months, also could earn an addition $5.05 million via performance bonuses based on his number of starts. While the Orioles have said they might use Santana as a reliever, the Twins viewed him only as a starter.
Santana turns 35 on March 13.
HONORING MONICA: Thirty members of the Orioles, led by manager Buck Showalter, will fly to Virginia on Friday to attend a memorial service for the team's late public-relations director Monica Barlow, who died of cancer on Feb. 28.