Miles Mikolas pitched six strong innings and Jordan Walker’s sixth-inning homer provided the lone run Saturday night as the visiting St. Louis Cardinals topped the struggling Kansas City Royals 1-0 to win for the 12th time in 13 games.

Ivan Herrera’s fifth-inning single and Walker’s drive were the only hits St. Louis could muster, as Kansas City starter Noah Cameron (1-1) delivered a second straight strong start to begin his major league career while also making his home debut.

Meanwhile, Mikolas (3-2) yielded just two hits and two walks and maintained control for the Cardinals, who also got two solid relief innings from Kyle Leahy and a perfect ninth from Ryan Helsley (nine saves) to clinch the usually intense I-70 Series.

Cameron, a native of nearby St. Joseph, Mo., lasted 6 1/3 innings after going the same distance April 30, when he yielded his only hit in the seventh inning of a 3-0 victory at Tampa Bay in his big-league debut. On Saturday, the Royals were held to four hits — three singles — while losing for the sixth time in seven games following an impressive 16-2 stretch.

The highly touted Cameron, who was called up from Triple-A Omaha after originally scheduled starter Seth Lugo was placed on the injured list due to finger inflammation, cruised into the sixth inning. That’s when one bad pitch resulted in the first run yielded in his big-league career.

Walker, who entered batting .186, sent a Cameron pitch well over the left-center field wall for his first home run since April 13.

Kansas City’s best threat came in the eighth inning when Drew Waters led off with a single and went to second on Kyle Isbel’s bunt single. But Jonathan India’s soft liner dropped in front of St. Louis second baseman Brendan Donovan, who tossed to second for a force, then the Cardinals got Waters out in a rundown between second and third.

Donovan then made a diving glove stop, leading to a force at second base for the final out of the frame.