The Orioles' bullpen turned in three scoreless innings tonight in relief of starter Chris Tillman to complete a 5-3 victory over the Royals before 12,344 at Camden Yards.
The Orioles have their first four-game winning streak of the season.
Troy Patton retired the side in order in the seventh.
Darren O'Day struck out the first two batters in the eighth before allowing an infield hit to Eric Hosmer and hitting Lorenzo Cain on the leg.
Brian Matusz entered the game to face left-handed hitting Mike Moustakas and retired him on one pitch, a 91 mph fastball that resulted in a foul pop up to catcher Matt Wieters. Moustakas had been 3-for-3 with a home run.
Matusz has now stranded 28 of 29 inherited runners since moving to the bullpen last summer.
O'Day now leads Orioles pitchers with four hit batters.
Closer Jim Johnson got the last three outs for his 13th save. Johnson has tied Randy Myers for the longest streak of successful save conversions in franchise history at 34.
Elliot Johnson opened the ninth with an infield hit, but George Kottaras grounded into a 4-6-3 double play and Jarrod Dyson struck out.