KANSAS CITY -- Nearly three months off a Major League mound didn’t seem to affect Jack Flaherty as much as the Royals maybe would have hoped in their series-opening game against the Cardinals on Friday night.

The St. Louis ace fashioned a gem against the Kansas City offense in its 6-0 loss at Kauffman Stadium, stymying the Royals' lineup for six scoreless innings in his first start since May 31.

The Royals managed just two hits in six innings off the right-hander and five in total Friday night. They had the bases loaded in the eighth inning, and while Nicky Lopez worked an eight-pitch at-bat against reliever Giovanny Gallegos, the Royals walked away with no runs on the board.

“Impressive how sharp he was the first time back after that long off a Major League mound,” manager Mike Matheny said. “He had really controlled counts, made quality pitches with his fastball. It was all day. Our guys were taking some called strikes that were really well executed.

“He was in control. He was efficient and didn’t give us much. He didn’t make many mistakes.”

Flaherty’s night was an outing worthy of a cap-tip, but the Royals’ offense has shown troubling trends lately, despite a few nights of offensive breakouts over a 4-10 stretch of games. The Royals are batting .163 (16-for-98) with runners in scoring position in their last 14 games since July 29, including 1-for-22 in their last three and 0-for-5 on Friday.

Their opportunity to make something happen was in the eighth against Gallegos, but with two outs, there was only one shot. With Salvador Perez on deck, Lopez hit a fastball 95.3 mph, but he got too much loft on the ball for it to fall just in front of the warning track into center fielder Harrison Bader’s glove.

“That’s our chance,” Matheny said. “We have to have something happen there with two outs, though, and Nicky’s putting together a good at-bat, actually found the barrel but just got too much air under it. Would have loved to have seen Sal walk to the plate right there. We’ve seen some exciting things happen when he gets into those positions. And it would have been fun to see.”

Starter Mike Minor kept the Royals within reach for six innings, allowing three runs and tossing his 100th career quality start. Back-to-back homers from Nolan Arenado and Tyler O’Neill broke up Minor’s no-hit bid with one out in the fourth, but he became the 14th active left-hander to reach 100 quality starts for his career, joining names such as Clayton Kershaw (271), Jon Lester (257), Madison Bumgarner (196), Chris Sale (162) and Dallas Keuchel (141).

“Honestly, it doesn’t mean a lot to me,” Minor said about the milestone. “I feel like it took way too long. That should have happened a long time ago. I’ve had some injuries, missed some time. I was a reliever for a year. So I get that part. But I think I should be better than that.”

Minor (8-11) mowed down the Cardinals early on Friday, with five strikeouts through 3 1/3 innings. Arenado was the lone baserunner on a walk in the first before his solo blast in the fourth on a slider that was left hanging in the middle of the plate. O’Neill crushed a changeup in a similar location to straightaway center two pitches later.

“One of the better games early on that I’ve had in a while,” Minor said. “I thought my stuff was pretty good until [the fourth inning], and then I was fighting mechanics and thinking about mechanics rather than making pitches. And then I started leaving pitches out over the plate.”

What Flaherty did on Friday was too much for the Royals to overcome. He was brilliant for six innings, needing 81 pitches and running his career streak to 20 consecutive scoreless innings against the Royals, a team he is 4-0 against with an 0.72 ERA. He sped them up with his fastball and then slowed them down with his curve, throwing his slider in with some bite and mixing in his changeup. Perez’s broken-bat single in the first and Emmanuel Rivera’s rocket of an infield single in the sixth were all the Royals could muster off Flaherty.

After the Cardinals went ahead on back-to-back home runs from Arenado and O’Neill in the fourth inning, Flaherty needed six pitches to dispatch the Royals in the bottom of the frame.

“I feel like the momentum today was just on our side,” Arenado said. “I know Minor was pitching there pretty good today, but once we started to score some runs and Jack was able to shut them down, I felt like the momentum stayed on our side throughout the game.”