It took the sting away from starter Yordano Ventura getting knocked out in the fifth, after allowing four runs (three earned) on seven hits in 4 1/3 innings.
Lefty Eduardo Rodriguez helped the Royals get momentum back on their side when he allowed the first three batters to reach in the sixth, two on walks. Matt Barnes came on for Boston and the Royals, backed by Mondesi's laser to the gap in right-center, swiftly chased him.
The Royals are 5 1/2 games back in the American League Central, but just three behind the Orioles for the second Wild Card spot.