The first game of the National League championship series was called off today when a Missouri deluge halted play between the St. Louis Cardinals and the Atlanta Braves.

The Braves were leading, 1-0, with one out in the bottom of the fifth when a steady drizzle came down from ominous thunderheads. Umpire Billy Williams waved the players off the field, and 2 1/2 hours of downpour later, league President Chub Feeney sent the teams home.

Now, what was to have been Game 2, Thursday at 8:15 p.m. EDT (WJLA-TV-7, WJZ-TV-13), with Bob Forsch (15-9) pitching for the Cardinals and Pascual Perez (4-4) for the Braves, becomes Game 1. Instead of moving to Atlanta on Friday, the teams must play here again at 8:15 that night, with everything pushed back a day and the Atlanta portion of the series beginning Saturday. Should the series go the maximum five games, with no further postponements, it would end Monday, on the eve of the World Series' scheduled Tuesday start.

Had the rain held off for another two outs, it would have been an official complete game (five innings). Afterward, Atlanta Manager Joe Torre said a regular-season game probably would not have been called so hastily.

But Torre said he was not bitter at losing the opportunity for a five-inning victory. "We don't want to steal a game." he said, "And if we did finish five, we might still be sitting here at 2 a.m. trying to finish it, in fairness to the other team."

It was the first time that a championship series game was rained out in progress. Braves players seemed surprised when Williams made his decision, since the rain was light at the time. They milled around the field briefly but scattered when a deluge developed in minutes.

"The Braves only needed two outs, and I know how they feel, but the umpire made the right decision," Feeney said. "The weather report was very bad."

If a fifth game is necessary, St. Louis Manager Whitey Herzog likely will start Forsch again with only three days rest, which would be to the Cardinals' disadvantage. Forsch said during the rain delay today that although some pitchers are rested after three days, "I need my four."

Braves starter Phil Niekro (17-4) was in command after the first inning, in which St. Louis loaded the bases. Niekro said he felt fine and could pitch again Thursday after his 4 1/3-inning stint, but Torre said Niekro probably wouldn't pitch until Saturday, giving him two days' rest.

With Lonnie Smith on third base, Niekro got George Hendrick to pop up, ending the threat. Niekro got his knuckleball under control after the first inning and allowed only one hit thereafter. He was in jeopardy only in the third.

Tommy Herr led off with a single, but was out trying to steal second. Smith lined sharply to second one out later, the ball scooting under Glenn Hubbard's glove and rolling almost to the right field wall for a triple that would have scored Herr. Smith was stranded again when Keith Hernandez grounded out.

The Braves scored in the first inning off Joaquin Andujar, who also settled down after early problems. Leadoff man Claudell Washington doubled off the left field wall, was sacrificed to third and came home on Chris Chambliss' two-out single.

Andujar allowed one other hit. He is expected to pitch again Sunday after three days' rest, his preference. Thus, the rainout benefits the Braves again. "It favors Atlanta, it really does, because Niekro can come back quick. I lost my best pitcher," said Herzog.

The revised pitching rotations now have Perez and Forsch in Game 1; Cardinal John Stuper (9-7) vs. Tommy Boggs (2-2) in Game 2; Dave LaPoint (9-3) against Niekro in Game 3, and if necessary, Andujar against Rick Camp (11-13) in Game 4 and Forsch and Perez in the finale.

Perez is the Brave who got lost on his way to his own ballpark in August, showing up to work a half-hour late in a rented car. Everyone had a laugh, as the Braves won that night behind Niekro and ended a slump in which they'd lost 19 of 21 games.

Camp tried to lift huge slugger Dale Murphy after the Braves won the division championship Sunday, and wrenched his back doing it. Said Camp, "He started to fall and I fell down trying to keep him from falling. I figured, better I get hurt than Murph."

Camp will throw on the sidelines Thursday. He expects to be ready for the game Sunday.