Chris Tillman had one of the best performances of his career in his last start.
He's also had some of his worst against the Kansas City Royals.
Tillman will try to pitch the Orioles to a season-best fourth straight win Wednesday night against the visiting Royals.
After going 0-1 with a 7.07 ERA in his first three starts this season, Tillman (2-1, 3.63 ERA) is 2-0 with a 1.31 mark in his past three outings.
He was dominant in a 5-1 victory over his hometown Los Angeles Angels on Thursday. The right-hander allowed three hits in eight scoreless innings, struck out three, walked two and retired 20 of his last 21 batters.
''I think he had something like 23 out of 29 first-pitch strikes, and that was the difference,'' manager Buck Showalter said. ''You could tell early on he had a crisp fastball.''
Success against the Royals (17-12), however, has been elusive. In three starts versus Kansas City, Tillman is 0-2 with a 10.93 ERA, giving up six homers and 23 hits in 14 innings.
Baltimore (20-13) played its first home game in two weeks Tuesday, winning the opener of this three-game series 4-3. Matt Wieters had a two-run double in the first inning and a tiebreaking RBI double in the eighth to score Adam Jones, who drove in the other run.
''When you don't walk people and you catch the baseball the way we did tonight, you give yourself a chance to win those types of games,'' said Showalter, whose team turned three double plays but committed its first error in eight games.
With their third straight win and 13th in 19 tries, the Orioles moved a season-best seven games over .500.
''This team grinds it out,'' said winning pitcher Tommy Hunter, who extended his scoreless streak to 12 1-3 innings. ''This team is fun to watch for everybody. Nobody should ever leave the stadium, I'll tell you that much, under any circumstances.''
Jones is batting .330 with three homers, 13 RBIs and 13 runs during a 21-game hitting streak against Kansas City.
Alex Gordon hit a tying two-run homer for the Royals, losers of two in a row following a four-game win streak.
Gordon is 9 for 22 with four home runs in his last five games against Baltimore and 2 for 6 with a homer off Tillman.
Kansas City, which has yet to drop three straight, will send Luis Mendoza (0-1, 7.00) to the mound hoping he can rebound from his worst outing of the season.
In his first start in almost three weeks, the right-hander was tagged for six runs and seven hits - including three homers - over four innings but escaped without a decision in a 9-8 win over Tampa Bay on Wednesday.
That was his first appearance since pitching 2 1-3 scoreless innings at Detroit on April 24.
Mendoza beat the Orioles in his first start against them in four years on Aug. 11, allowing three runs and seven hits in six innings of a 7-3 victory over Tillman at Camden Yards.