Hardy homered, his 17th of the season, in the four-run sixth with Davis aboard. He picked up another RBI in the third when Davis scored on his ground-out.
The Orioles’ 18-hit attack matched their season high.
Scott Feldman (2-1), who was acquired in a July 2 trade from the Chicago Cubs, was the beneficiary of the offense, picking up the victory.
Feldman limited the Royals to five singles and two runs over eight innings.
Wade Davis (4-9) took the loss, giving up four runs, two unearned, on seven hits and three walks in 2-2/3 innings.
Monday’s other results:
‧ Athletics 4, Astros 3
‧ Twins 4, Angels 3
A.J. Ellis hit a two-run homer and drove in a career-best five runs, while Ryu Hyun-jin pitched 5-1/3 innings as the Los Angeles Dodgers beat the Toronto Blue Jays 14-5 for their fourth straight victory and 21st in 26 games.
Skip Schumaker added a three-run shot as the Dodgers moved a season-high four games above .500 and won their eighth straight road game, their longest streak since a nine-game run in July 2004.
Ellis went deep in the second inning and had RBI singles in the third, sixth and seventh. He also reached on first baseman Adam Lind’s fielding error in the fourth.
Toronto made a season-high five errors and lost their fifth straight game. The Blue Jays have lost 12 of 16 overall.
Ryu (8-3) had gone 4-1 with a 2.25 ERA in 10 starts, before matching a season worst by giving up five runs in five innings in Arizona on July 10. He was better against the Blue Jays, allowing four runs and nine hits, all singles. Ryu walked two and struck out three.