The hard-hitting Philadelphia Phillies demonstrated the art of playing baseball under pressure last night, and jumped out to a 1-0 lead in the National League Playoffs in Los Angeles.

The Phillies capitalized on some slack fielding by Dodger shortstop Bill Russell and displayed air-tight defense as well as timely hitting en route to a 7-5 triumph over the West Division champs.

Perennial superstar Mike Schmidt led the Phils' clutch performance with some sparkling fielding at third base and a game-winning line single to left field in the ninth inning.

But it was L.A.'s Russell who emerged as the new hero in the City of Brotherly Love. In the first inning, his two-out throwing error was followed by a towering two-run blast by Greg "The Bull" Luzinski. In the fifth, Russell was caught with his foot off the bag by both second-base umpire Harry Wendelstat and the NBC camera crew on an attempted double-play.

Philadelphia's Dave Johnson then cost Russell, a few thousand on next year's contract by driving in both men who reached base as a result of the misplay, to put the Phils ahead, 4-0.

Goat

The beleaguered Russell attempted to save further embarrassment in the next inning by pretending not to see a high-hopper off the bat of Tim McCarver which bounced right by him. Despite a generous offical scorer who scored a hit on the play, Russell was again the goat when McCarver crossed the plate on Steve Carlton's base hit.

Ron Cey treated the crowd at Chavez Ravine to its only thrill of the night with a grand slam in the seventh that knotted the score at 5-5.

But the screaming throng of more than 53,000 was soon silenced as the Phillies' superior defense shut out the Dodgers after that, setting the stage for Philadelphia's two-run ninth.

A controversial balk call on Dodger reliever Elias Sosa provided the Phils with an insurance run after Schmidt's timely RBI.

The second game will be played at 8 p.m. tonight.