Michael Wacha is on of many talented rookie pitchers on the St. Louis Cardinals. (Matt Slocum/AP)

Michael Wacha is one of many talented rookie pitchers on the St. Louis Cardinals. (Matt Slocum/AP)

This postseason, Michael Wacha of the St. Louis Cardinals is 4-0, his latest win coming in Game 2 of the World Series on Thursday night at Fenway Park.

You want understatement on that subject? Here’s Cardinals Manager Mike Matheny.

“The kid continues to impress,” Matheny said. ”He and [catcher] Yadi [Molina] work well together and make good adjustments along the way. He stuck with his strengths and really went out and was aggressive, and that’s exactly what we needed him to do.”

Wacha’s strengths are his fastball and his changeup. On Thursday night, the Cardinals rode Wacha and the relief pitching of two other rookies, Carlos Martinez and Trevor Rosenthal, to a 4-2 win. Afterward, Wacha, whose postseason ERA is 1.00, was asked if his success had changed everything.

“Yeah, I went to go eat at a little restaurant, and they had a milkshake named after me, which was pretty weird, so I had to try it out,” he recalled. “It was pretty good.”

The milkshake, called The Wacha Wacha, is vanilla, with chocolate chips and Cracker Jack.

On Friday morning SI.com’s Tom Verducci provided the overstatement Mike Metheny avoided. He said Wacha might be the greatest young pitcher in postseason history.

If the Series goes to a sixth game, the Red Sox will likely see Michael Wacha again. Could he win for the fifth time in the  postseason? Among those who might not be surprised if it happened is Sox Manager John Farrell.

“When you get guys in the first full year of pro baseball to be able to maintain this kind of stuff in October, it’s remarkable, with what he’s doing,” said Farrell. “Obviously a very talented guy.”

Talented, poised, still only 22, and the winner of the game the Cardinals needed to avoid going back to St. Louis down 2-0. No wonder they’ve named a milkshake after him.