Flaherty threw 99 pitches (73 strikes), also matching his season high, in the outing, allowing one earned run on two hits and one walk to lead the Cardinals past Northwest Arkansas, 4-3.
"For me, I want to throw three pitches or less to every hitter," Flaherty told MiLB.com. "I want to attack and fill up the zone so my defense get to work, and they've done a really good job for me this year. When you fill up the zone, you're going to have days where you strike everyone out and you'll have days where they put a lot of balls in play."
Northwest Arkansas' lone run against Flaherty came on a leadoff home run by first baseman Frank Schwindel in the second inning. The 21-year-old right-hander retired the next 14 batters he faced -- at one point striking out five in a row -- before permitting Donnie Dewees to reach base on a nine-pitch walk with two outs in the sixth inning.
Overall, Flaherty, the Cardinals' first-round Draft pick (No. 34 overall) in 2014, struck out the side in the first and third innings and fanned at least one batter in each frame.
Flaherty is now 5-0 in his first six starts at the Double-A level after recording his Texas League-leading fifth victory on Friday. He also paces the circuit in ERA (0.69), WHIP (0.74) and strikeouts (40), and he's issued just five walks in 39 1/3 innings while working into the seventh inning on four occasions.
• Box score
At the plate for Springfield, Oscar Mercado laced a sixth-inning triple into the gap in right-center to extend his franchise-record hitting streak to 20 games.
Mike Rosenbaum is a reporter for MLB.com. Follow him on Twitter at @GoldenSombrero. This story was not subject to the approval of Major League Baseball or its clubs.