"He's becoming a guy a lot of teams wish they drafted," teammate David Freese said. "What he's done is remarkable, especially on this stage."
Wacha stared down a bases-loaded test in the sixth inning and pitched into the seventh, and the kids in the bullpen also were impervious to October pressure, keeping the Los Angeles Dodgers bats silent for the second straight day and winning 1-0 Saturday for a 2-0 lead in the NL championship series.
"I'm kind of at a loss for words to describe him," said fellow rookie Kevin Siegrist, who got a big out to end the seventh. "It's kind of ridiculous how well he's done so far."
The Cardinals managed only two hits off Kershaw and the Dodgers, but Jon Jay's sacrifice fly set up by Freese's double and A.J. Ellis' passed ball in the fifth stood up.
The Dodgers' scoreless streak in the NLCS reached 19 innings after they averaged 6 ½ runs in a four-game division series against Atlanta. Rookie fireballer Trevor Rosenthal struck out the side in the ninth with a heater reaching 101 mph, fanning pinch-hitter Andre Ethier on three pitches to end it.
A day after outlasting Los Angeles 3-2 in 13 innings, the Cardinals moved two wins away from the World Series.
Game 3 is Monday at Dodger Stadium, with Cardinals ace Adam Wainwright facing rookie Hyun-Jin Ryu. The Dodgers have already used their top two starters and have nothing to show for it.
"We don't get too far ahead of ourselves," Cardinals manager Mike Matheny said. "We don't deny also what's happened here the last two days.
"Those were two very good wins, two very tough wins when you face starters like that."
Hanley Ramirez and Ethier were out of the Dodgers' lineup with injuries after starting in the opener. Los Angeles missed a handful of opportunities, going 0 for 6 with runners in scoring position for a two-day total of 1 for 16. Star rookie Yasiel Puig struck out in all four of his at-bats.
"We had our chances," Kershaw said. "We had our chances, for sure. You've got to give a lot of credit to Wacha."
The teams may have been hindered by shadows creeping across Busch Stadium in a late-afternoon start, with lights providing no real help. Both also were no doubt fatigued, which might have shown on the crucial passed ball by Ellis that wound up resulting in an unearned run.
Wacha was nearly untouchable for the third straight start, allowing five hits with eight strikeouts and a walk in 6 2-3 innings.
The 22-year-old right-hander was one out away from a no-hitter in his last start of the regular season, losing it on an infield hit by Washington's Ryan Zimmerman. Wacha ignored a crowd chanting his name in Game 4 of the division series at Pittsburgh, holding the Pirates hitless for 7 1-3 innings to bring the series back home.
In 22 2-3 innings in his last three starts, Wacha has given up two runs on seven hits with 26 strikeouts and five walks.
The 6-6 Wacha struck out Puig and Juan Uribe with the bases loaded to end the sixth. Catcher Yadier Molina helped by making a couple trips to the mound.
"That was a game-changer right there," Molina said. "To get out of that inning was unbelievable."
Kershaw led off with a single, and runners were on second and third after second baseman Matt Carpenter slid in shallow right to glove Carl Crawford's infield hit but threw it away for an error trying to get a forceout at second.
Adrian Gonzalez was walked intentionally to load the bases and the Dodgers 4-5 hitters coming up. Puig struck out on a fastball in the dirt and Uribe had a feeble cut chasing a 1-2 pitch out of the zone.
Carpenter tripled on Kershaw's first pitch of the game but didn't budge when the lefty retired the next three on nine pitches.
The Cardinals had another runner at third with nobody out in the fifth after Freese doubled and advanced on a passed ball by Ellis, This time they converted on Jay's sacrifice fly to shallow left as Crawford's throw was well offline.
The previous pitch the Cardinals tried to squeeze in a run with the Dodgers infield playing in, but Jay fouled off a 1-1 pitch.
Kershaw worked six snappy innings, needing just 72 pitches. He gave up two hits and struck out five.
The majors' ERA leader had plenty left, too, but the Dodgers needed runs and manager Don Mattingly opted for pinch-hitter Michael Young after Nick Punto's two-out single in the seventh.
"I always want to stay in the game, but I understand where Donnie's coming from," Kershaw said. "I get it. We can't give up any more outs and Michael Young is one of the best players the last 10 years."
The Cardinals lifted Wacha for another stingy rookie. Siegrist, who had a minuscule 0.45 ERA in his debut season, threw a pair of wild pitches before getting Young on a flyout to end the seventh.
Relievers Randy Choate and Carlos Martinez pitched the eighth for St. Louis before turning it over to Rosenthal.
The Cardinals handed Kershaw two of his nine losses this season and have beaten him four consecutive times overall.
NOTES: SS Ramirez was a late scratch with sore ribs after getting plunked in the first inning of Game 1. Ethier has been slowed by a sore ankle. ... Carpenter has a hit each of the first two games after entering the NLCS in a 3 for 39 slump. ... Choate, the lone veteran reliever the Cardinals used in Game 2, has gotten two outs on four pitches in two appearances.