BALTIMORE -- Jonathan Villar backpedaled briskly into second base, content, after some split-second consideration, with the assumption that his leadoff double was exactly that. Which is why the Orioles were forced to swallow a bitter pill when Villar was later sent back to the dugout, their auspicious start Monday night wiped out by chief crew review ruling that a fan interfered with Villar’s drive to left field off Boston starter Josh Smith.

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In his next at bat, Villar made sure to leave no ambiguity -- taking Smith well beyond the center field wall at Oriole Park. The second baseman’s second-inning grand slam marked Baltimore’s first of the season and provided all the support starter John Means would need to secure an economical 4-1 win over Boston.

Staked to that early lead, Means put together his most effective performance yet. The rookie held Boston to one run over a career-high seven innings, allowing only a fifth-inning Eduardo Nunez sacrifice fly to muddy his line. Besides that, Means allowed three hits and struck out four, walking none. He shaved his ERA to 2.88 across five starts in the process.

"He's still developing, which is cool and impressive and what we're looking for from our young players,” Orioles manager Brandon Hyde said. “Not only [to] have results but to improve over the course of the year.”

That development has been plain to see for the 26-year-old Means, whose emergence stands out as the most pleasant surprise of the Orioles young season. It was particularly obvious Monday when Means, essentially a two-pitch pitcher so far this year, upped his slider usage four-fold to cool Boston’s red-hot lineup. Means threw 21 sliders -- more than twice as many as in any other start this season.

Boston’s top five hitters finished 0-for-15 against the southpaw.

“That was an impressive performance,” Hyde said. “You’re seeing a four-pitch pitcher right now.”

Said Means: I’m going to need that as I go forward. The first month, the changeup kind of surprised everybody. As I move forward and establish myself, I’m going to need the breakers more.”

In doing so, Means became the second consecutive Orioles starter to complete seven frames -- something the club did just once over its first 33 contests. Mychal Givens secured the final four outs to notch his fourth save, and his third of more than three outs.

“I just feel comfortable up here,” Means said. “I feel like these games really matter. I was never a prospect, so I feel like my back is against the wall every time I go out there. And I pitch better that way."

Because the Orioles were blanked over the final four innings by Ryan Weber, Means wouldn’t have earned his fourth victory without Villar, who continues to quietly enjoy a productive first full season in Baltimore. His fourth homer counted as the second grand slam of his career (the first coming September 4, 2016, against Pittsburgh as a member of the Brewers). The 28-year-old ranks among the American League leaders in several offensive categories, including multi-hit games (fifth), hits (tied for seventh) and stolen bases (tied for seventh).

“Johnny, like a lot of our guys, I feel like he’s on the upswing of his career,” Hyde said. “Just scratching the surface, still finding things to help him be a better player. John has so many tools … He’s playing really good baseball.”