The last thing John Lowenstein expected to see as he danced araund the bases, pumping his fists over his head as 52,787 people roared, was tiny Manager Earl Weaver jumping up and down between second and third base, waiting to hug him.

"I've seen Earl a lot of places this year," said Lowenstein, whose three-run pinch hit homer in the 10th inning brought Baltimore a delirious 6-3 win over California tonight in the opener of the American League playoff. "But I've never met him in the base path. He's the smallest guy I ever saw around third base."

The Orioles greeted this first victory of the seven that they need to be World Champions with a glee usually reserved for the madhouse scenes after titles are decided.

"The ball just kept sailing and sailing," said Lowenstein, the man who wears the "Dead Goat Saloon" T-shirt under his uniform. "Actually, I knew it was out as soon as I hit it.

"The last home run I hit to left field was in . . . let's see . . . 1958, I think, in Little League," he said.The high fly landed in the fourth row of bleachers about 10 feet fair, making a loser of Angel reliever John Montague and a winner of bullpen ace Don Stanhouse.

"If I hit it to left, it's an accident."

Lowenstein's swat, on an 0-2 fork ball that Montague will always wish he had wasted, broke up what had been a 3-3 pitchers duel between Jim Palmer and the Angels' Nolan Ryan for most of the night.

This was the night that Lowenstein who has two swelled and painful ankles, had to be replaced in the starting lineup at the last moment by Pat Kelley.

But in that trip around the sacks, he felt no pain, skipping and leading cheers as he cavorted. Minutes after the field had finally emptied, Lowenstein, the serious-faced student with a masters degree in anthropology, was back out in front of the dugout, pumping both fists over his head like a victorious Rocky.

"I think our chances are pretty good of sweeping them," said Dough Decinces, who hit Montague's first pitch of the 10th for a single, took second on a sacrifice, then waited through a fly out and an intentional walk to Al Bumbry. "I'll tell you one thing. They aren't going to sweep."

Now that the Orioles have won the first game of a postseason series for the 10th consecutive time since 1966, it will be Angel Manager Jim Fregosi who will have the most trouble sleeping before Thursday's 3:30 p.m. second game.

"I thought the (left-to-right) cross-wind might have brought Lowenstein's ball back into the ballpark," Fregosi said wishfully.

What he really must have wondered was why he had left his southpaw reliever Dave LaRoche in the bullpen. Had Fregosi waved his left hand, the O's would have had to bat Bennie Ayala for Lowenstein -- thus placing a much less dangerous gentleman at the plate.

Weaver must receive the managing accolades tonight. He started Palmer, despite the three-time Cy Young winner protest and got nine gritty seven-hit innings from him.

"I kept us in the game," Palmer said proudly. "That's what I wanted to do . . . For some reason, my arm hasn't hurt for the last 10 days. I don't know why. That's all I'm going to say," he added implying that his season-long arm miseries might have been related to his low salary.

This evening was a revealing minature of the careers of Palmer minimized his jams on a night when he had less than overpowering stuff Ryan who left after seven innings with a "calf cramp" seemed to maximize his few difficulties.

When Dan Ford greeted Palmer with a first inning 400-foot homer, "I didn't know what to think," Weaver said.

When Ford doubled off the right field wall for another RBI in the third every Bird knew what to think. They were behind, 2-0, and in trouble; Ryan was blistering hot and had fanned the first four O's of the game.

Those who wish a textbook account of how Ryan can ever allow a run with fast balls consistently on the brink of 100 mph are referred to this game for illumination.

The slightest bad break seems to open the Ryan door. Tonight it was a dropped pop-up by second baseman Bobby Grich to open the third inning, it went for a two-base error.

Who should drive in the two runs off Ryan to tie the game, 2-2? No one but No. 9 hitter Rick Dempsey, who lashed a double high off the left field fence, and .167 hitter Mark Belanger, who followed with an RBI liner past Ryan's ear. Dempsey's elegant belly-flop across the plate united this packed-to-the-rafters house in a bellow that seldom stopped.

Ryan was back in the very next inning, allowing one of those totally selfinflicted runs that are his trademark.

As soon as leadoff man Kelly walked, he could not wait to run.

He immediately stole second -- a crucial base it proved. Ryan wild pitched him to third, then watched as DeCinces lashed a line drive RBI sacrifice fly to right for a 3-2 Oriole lead.

Kelly may have taken, but in the sixth, he have back. He dived too late for Grich's two-out liner up the gap that went for an RBI double.

The slightly disguised hero of this vital Oriole victory in the Russian roulette playoffs was the small manager, a man who almost always avoids his players' celebrations. He was lurking between second and third when insanity hit Memorial Stadium at 11:49 p.m.

By picking Palmer over 23-game winner Mike Flanagan to pitch this opener, Weaver has shifted the weight of this short series entirely onto the Angels. Their halos are badly tilted already.

"I can't ever remember doing that before," said Weaver, sheepish about creating a new position in baseball -- second base coach.

"Now, I didn't bother even asking John if his ankles hurt," he added, "because I know he'd say they were okay. Hell, he told me he was okay three days after he was hurt and his ankle was as big as a balloon."

This evening may have been the most frightening of their 102-win season for the Orioles. For hours Ryan's fire and their own blunders on the base paths endangered their six months of labor.

But, finally, after 117 of Ryan's Expresses, and 123 pitches from the wise Palmer, it was one swing of the bat by a member of the Orioles' long, long bench that decided this game, and perhaps this delicately balanced series.