ST. LOUIS — To hear Lance Lynn tell it, pitching really isn’t so tough.

Just throw some fastballs, then some more fastballs, and if needed, a few more fastballs.

That simple formula worked to perfection in a 1-0 win over the Brewers Tuesday night at Busch Stadium to push the Cardinals’ home record to an MLB-best 21-7. Lynn said 117 of his 118 pitches were fastballs as he went a season-high 7 2/3 innings, shutting out Milwaukee on just five hits.

So what was that other pitch?

"It was an out," Lynn said, smiling. "Who cares?"

Certainly not Cardinals manager Mike Matheny, who said Lynn might have turned in one of his best outings yet to improve to 4-4 with awful run support while lowering his ERA to 3.03. The right-hander never allowed a runner past second base and struck out two of the three Milwaukee batters to come up with runners in scoring position.

It’s not as though Lynn doesn’t have off-speed pitches in his arsenal, and he said he threw both curveballs and changeups in the bullpen during a pregame warmup session. They can be useful at times, but he prefers when they’re not needed.

The truth is, Lynn’s coy descriptions of throwing consistent fastballs wherever he wants — with catcher Yadier Molina providing only occasional guidance — don’t quite tell the whole story. Despite Lynn’s insistence that "a fastball’s a fastball," Matheny said that if Lynn or anyone else just threw 93-mph fastballs for an entire game, he wouldn’t last long against major league hitters.

"He’s finding a great feel for just manipulating the fastball with cuts and sink and four-seam," Matheny said. "Just not many guys who can get away with what he’s doing, but he’s locating it so well and taking off a little bit to put more run on, putting on a little. Pretty nice job."

Matheny said Lynn’s fastball actually works out to about four different pitches, all ranging from about 87 mph to 93 mph with significantly distinct movement. When Lynn has his command, it’s rare for hitters to make solid contact.

Milwaukee did well to put the ball in play better than most teams this year, but the Brewers couldn’t hit it nearly hard enough or to the right spots for an extra-base hit. They struck out five times and hit into another nine groundball outs as Lynn cruised past 100 pitches for his fifth straight start.

Leadoff hitter Carlos Gomez forced 20 of those pitches — all fastballs, of course — in his first two at-bats, but the center fielder never put the ball in play until he laid down a bunt single in the seventh. Lynn struck out Gomez his first two tries, including a critical at-bat to protect the Cardinals’ lead with Jean Segura on second in the third inning.

"(Lynn) just kind of kept challenging and challenging, and I think that says a lot about the movement that he has on the ball because he was turning it up and backing it off a little bit," Matheny said. "That’s just kind of his bull mentality. He’s coming at you."

That’s his game plan every time he takes the mound, no matter who steps into the batter’s box. High pitch counts have never troubled him, either, and the end result of an at-bat is all that matters, just like the game itself.

Perhaps his most nerve-racking moment came after he’d tipped his cap on the walk to the dugout while another sellout crowd gave him a standing ovation. A pair of singles put runners on the corners with one out in the ninth, but a well-turned double play from third baseman Matt Carpenter to second baseman Kolten Wong to first baseman Mark Reynolds earned Trevor Rosenthal his 16th save.

Naturally, when asked about his reaction, Lynn delivered a simple answer.

"I enjoyed it," Lynn said. "How about you? I’ll take it every time."

You can follow Luke Thompson on Twitter at @FS_LukeT or email him at lukegthompson87@gmail.com.