ST. LOUIS -- With their rotation rolling and their full-strength offense flexing its muscles, the Astros concluded their Interleague visit to St. Louis with a series victory, secured via a 6-2 win at Busch Stadium on Sunday.

Home runs, including ones hit by George Springer, Yordan Alvarez and José Altuve in the finale, highlighted the club’s pair of wins in the series. But the job Houston’s starters did to shut down a Cardinals offense that had averaged 6.67 runs over its previous nine games was just as vital.

• Box score

With Wade Miley's five scoreless innings on Sunday, the Astros’ starters limited the Cardinals to one run over 18 frames. Over the last 11 games (of which the Astros have won nine), their starters are 9-0 with a 1.42 ERA.

As for Sunday’s victory, here were three key developments that helped the Astros capture their third straight series victory.

Seeing the slider
The Astros expected to see a heavy dose of sinkers from Cardinals starter Dakota Hudson -- and they did. What they didn’t necessarily anticipate was how many sliders he’d mix around them. And that approach played right into Houston’s hand.

Hudson, whose 39-percent slider usage on Sunday represented a season high, served up three hits on the pitch. Two of them left the park.

Alvarez, making his first start of the series, drilled a solo shot off a slider to put Houston ahead, 2-0, in the third. Two innings later, Altuve teed off on a 2-2 slider for his 16th home run of the season and the 1,500th hit of his career. That blast gave the Astros a 5-0 lead.

“I felt like all but the slider to Altuve I executed pretty well,” Hudson said. “I felt like, American League team … [maybe they were trying to] hit my fastball and kind of cheat to it a little bit. That's why I tried to make my adjustment.”

Why Hudson leaned so heavily on the slider seemed a bit curious given the Astros’ success against the pitch this season. Entering the day, the Astros had a .242 xBA and .398 xSLG against the pitch. Those figures ranked first and second, respectively, in the Majors.

“We’re tough to pitch to,” Houston manager AJ Hinch said. “I like the way our offense’s approach was. We took a few walks here and there. We hit a couple balls out of the ballpark. We kind of got him to a breaking point late in the game with a Jose homer.”

Cue up the K's
Miley has enjoyed an uptick in strikeouts this season, something that Hinch believes is the result of the lefty seeking more swing-and-misses by attacking hitters’ weaknesses.

Those strikeouts were critical in helping Miley sidestep a threatening Cardinals offense. He twice struck out former teammate Paul Goldschmidt, including in a critical third-inning spot in which Goldschmidt came to bat with two on and nobody out. Miley threw six pitches inside to Goldschmidt, who had homered in six straight games, before freezing him for a called third strike on the outer part of the plate. 

“I was trying to crowd him up and in on his hands,” Miley said. “I wanted to keep crawling in there. If he was going to get me, he was going to have to rip his hands through pretty good.”

Later in the inning, Miley enticed Paul DeJong to swing through a full-count cutter with the bases loaded and one out. The Cardinals failed to score in the inning. Nor could they break through against Miley in the fourth, which ended with a strikeout of Jose Martinez to strand runners on the corners.

Miley, who struck out six over five innings, entered the start with his highest strikeout percentage (20.2 percent) since 2014. His rate of strikeouts per nine innings sat at 7.40, up from 5.58 a year ago.

“Wade came up with some big strikeouts to get out of some big innings and strand some runners,” Hinch said. “He’s calm out there. He’s got pitches to make. And even though he wasn’t at his best, to go five scoreless, it’s a game we’ll take.”

Miley’s keen eye
Perhaps the most unexpected development of the day was that it was Miley who set up the fifth-inning rally ahead of Altuve’s homer. Making his fifth plate appearance of the season, Miley worked a five-pitch walk against Hudson to lead off the inning. It was the first walk drawn by a Houston pitcher this season.

“That’s a big at-bat by Wade right there,” Springer said. “I know American League teams don’t really expect much out of a pitcher. But Wade’s [ability] to find a way on base actually sparked a rally.”

Miley was held up at third when Springer followed with a double -- “I was cheering at [third-base coach] Gary Pettis not to wave me,” Miley noted -- before strolling home on Altuve’s homer.

“He reminded me that he had a great eye to lead off the inning, and you can’t teach that,” Hinch joked. “You have to be born with that eye.”