The 23-year-old McFarland, selected from the Indians at the last Winter Meetings, allowed one hit and struck out five in a dominant 40-pitch outing. McFarland threw 28 strikes and struck out four consecutive batters at one point -- Aaron Hicks, Joe Mauer, Josh Willingham and Morneau.
One of the Orioles' final roster decisions this spring, McFarland is the third lefty in the Orioles bullpen and the final reliever to pitch this season. Chris Parmelee singled in the sixth and was the lone Twin to reach base against him.
McFarland, who split the 2012 season between Cleveland's Double-A and Triple-A affiliates, got off to a rocky start this spring, but turned it around and the organization opted to keep him. He recorded a 4.70 ERA over 15 1/3 Grapefruit League innings, making one start.
"Been impressed with [his composure] all spring," Orioles manager Buck Showalter said. "Only time he got really frustrated were the first couple of outings, when he knew he was better than that. He and [pitching coach Rick Adair] had a couple of sessions, and he got back to doing what he was doing to be wanted. Since then, he has been real consistent, especially pitching in some of those hitter-friendly situations you have in the spring.
"You never really know when you get into a situation like tonight. Fortunately, it was a good spot for him. He got a little better and a little better."
McFarland will keep the ball from his first strikeout -- Twins third baseman Trevor Plouffe -- along with a box of a dozen authenticated baseballs to give out to his family. McFarland said he will also cherish the memory of swinging open the bullpen door and jogging across the outfield grass to the mound at Camden Yards.
"It was an incredible feeling," he said. "Nothing beats it. The adrenaline, the excitement, I really can't even put into words. It really is just the best feeling you could ever feel."
Brittany Ghiroli is a reporter for MLB.com. Read her blog, Britt's Bird Watch, and follow her on Twitter @britt_ghiroli. This story was not subject to the approval of Major League Baseball or its clubs.