Baltimore's Dean Kremer threw seven shutout innings and Ryan O'Hearn broke up a scoreless tie with a two-run, seventh-inning home run as the Orioles beat the visiting Kansas City Royals 3-0 in the opener of a three-game series Friday night.

Yennier Cano and Felix Bautista each pitched an inning of relief to complete the combined four-hitter.

O'Hearn and Ryan Mountcastle had two hits apiece for the Orioles, who have won three of their last four games.

Michael Wacha matched Kremer through six innings before the Orioles got on the board.

Kremer (3-4), who entered the game with a 7.04 ERA in 6 starts, limited the Royals to three hits and one walk with two strikeouts.

Bautista was credited with his sixth save. The Royals were shut out for the fourth time this season.

Kansas City's Michael Massey and Freddy Fermin posted two hits apiece, but the Royals lost for just the second time in their last 11 games. Massey's second-inning double was the only extra-base hit for Kansas City.

Wacha (1-4) had thrown six scoreless innings Saturday against Houston, so he was in a groove as well. But his line ended up at three runs on seven hits with a walk and three strikeouts in 6 1/3 innings.

The teams combined for six hits through five scoreless innings, which were completed in less than an hour.

Adley Rutschman led off the bottom of the seventh with a double and O'Hearn, the next batter, homered to center field. It was O'Hearn's sixth home run of the season.

Two of the next three batters reached base against Wacha, who was replaced by Steven Cruz. After Heston Kjerstad's single loaded the bases, Emmanuel Rivera, playing in just his second big-league game of the season, provided a run-scoring single before Cedric Mullins lined into an inning-ending double play.

Despite the limited offense, each team struck out just four times.