Steve Carlton pitched a three-hitter to become the major leagues' first 20-game winner this season and hit a home run last night in Philadelphia as the Phillies defeated the St. Louis Cardinals, 2-0, before 40,109 and took over first place by a half-game in the National League East.

Right-hander Bob Forsch (14-9) gave up just three hits in losing.

It was the sixth time in his 17-year major league career that Carlton has won at least 20 games. He retired the first 11 batters before giving up a double to Keith Hernandez. Carlton, 282-182 lifetime, is the second-best left-hander in history, trailing only to Warren Spahn, with 363.

Carlton is the only pitcher to have beaten every team in the league at least once this season. He is 20-9 after starting the season 0-4, the worst beginning of his career.

He struck out 12 and walked none for his fifth shutout this season and 51st of his career.

"He just got stronger," Phillies Manager Pat Corrales said. "He's the best I've seen. It's amazing, too, a man almost 38, pitching like he's 28.

"That's what desire and talent does for you. He prepares himself. He works hard."

With two out in the fifth, Carlton worked the count to 3-1 against Forsch, then homered over the wall in right. It was his second homer this year, 11th of his career. "He really smoked it," said Cardinals Manager Whitey Herzog.

Lonnie Smith, a former Phillie, misjudged a drive by Pete Rose in the fifth and retreated to make a leaping one-handed catch; he then spiked the ball over his right shoulder in left field. Spectators booed him the next inning and threw objects Smith after he waved defiantly and doffed his cap at them.

"I just got to the point where I couldn't hold it in any longer," Smith said. "They criticized me and the way I was playing so I was saying, 'Go ahead and hit me.' "