PITTSBURGH » Rookie Michael Wacha took a no-hit bid into the eighth inning and the St. Louis Cardinals showed off their October poise, edging the Pittsburgh Pirates 2-1 today and setting up a winner-take-all Game 5 in the NL division series.

The Cardinals tied this playoff matchup and improved to 7-1 over the last three years when facing elimination in the postseason.

Pedro Alvarez hit his third home run of the series, connecting with one out in the eighth for Pittsburgh’s only hit in Game 4.

Wacha, who came within an out of a no-hitter in his final start of the regular season, and the St. Louis bullpen made Matt Holliday’s two-run homer in the sixth stand up.

Trevor Rosenthal worked around a two-out walk in the ninth, retiring Andrew McCutchen on a popup for his first postseason save.

Game 5 will be Wednesday in St. Louis, with ace Adam Wainwright starting for the NL Central champion Cardinals and rookie Gerrit Cole going for the wild-card Pirates. Both pitchers won last week in the NLDS.

The Cardinals finished with only three hits, and that was enough. Holliday got two of them, including his homer off Charlie Morton.

Wacha struck out nine and walked two. The 22-year-old righty didn’t permit a runner until walking Russell Martin leading off the sixth.

Wacha nearly no-hit the Washington Nationals in his last start on Sept. 24, surrendering only a single by Ryan Zimmerman with two outs in the ninth. He might have been even better in front of a frenzied crowd that relentlessly chanted his name, eager to send the Pirates into the NL championship series for the first time in 21 years.

Working so quickly the Pirates never had time to get settled, he breezed through Pittsburgh’s revamped lineup like it he was in extended spring training, not a pressure-packed elimination game. Mixing his fastball and changeup masterfully, Wacha overwhelmed the Pirates from the moment he stepped onto the mound.

Alvarez got the fans at PNC Park roaring with his homer, and Wacha followed by walking Martin on four pitches. Carlos Martinez relieved and Gold Glove catcher Yadier Molina made a key play, throwing out pinch-runner Josh Harrison when he tried to steal second.

Martinez struck out Jose Tabata to end the eighth, and Rosenthal took over to begin the ninth. Neil Walker drew a two-out walk before McCutchen made the final out.

McCutchen came into the game hitting .538 in the postseason but looked at a 97 mph fastball for strike three in the first. Marlon Byrd, Pittsburgh’s most consistent player since being acquired from the Mets in late August, watched a full-count heater in the second that sent him walking back to the dugout in disbelief.

It was a look repeated time and again by Byrd and the rest of his baffled teammates. Wacha struck out five of the first seven batters.

Martin remained Pittsburgh’s lone baserunner until the eighth. Wacha fell behind 3-1 and Alvarez hit a 93 mph fastball at the knees onto the concourse in right-center.

Morton, in the midst of a career renaissance a year following reconstructive elbow surgery, had been pounded by the Cardinals this season, going 0-2 with a 7.90 ERA. Faced with the biggest start of his life, he nearly matched Wacha’s run at perfection.

Save for a single to right by Holliday in the first and a walk to Beltran in the fourth, he had no major issues until he pitched around Beltran leading off the sixth. Beltran began the day hitting .333 in the series with a couple of home runs while Holliday had just two hits through three games.

Holliday’s second hit in three trips against Morton was more than enough to extend the Cardinals’ season. He turned on Morton’s fastball and sent it into a helping breeze that left no doubt.

McCutchen trotted slowly toward the warning track but could do little as the ball disappeared over the fence and into the St. Louis bullpen.

The Cardinals relievers lifted up their arms in celebration. It’s not like they had anything else to do the way Wacha was dealing.

NOTES: Wacha was the 19th overall pick in the 2012 draft. he earned his first major league win on June 11. … A.J. Burnett pitched Game 1 for Pittsburgh, but manager Clint Hurdle picked Cole to move ahead and start Game 5.