The calendar says there are four seasons, but there really is only one. For the Orioles, it began today in the nicest possible way, with a 5-3 victory over the Kansas City Royals, the defending American League champions.

There is "a kind of electricity about opening day," Oriole Manager Earl Weaver says. And, undoubtedly, the 50,317 paid customers, the largest opening day crowd in Memorial Stadium history, felt it. "Now that opening day is over," Weaver said, "you can say it's just another day, which it is. But Sunday, the butterflies won't be there like they were today."

The butterfies, and ceremonies, and ceremonial guests: 14 former hostages, plus Joe DiMaggio, who threw out the first pitch.

There was also quite a ball game.

Steve Stone, whose parents accepted his 1980 Cy Young Award before the game, won it with four innings of relief from Sammy Stewart, whose relatives should have been here, too. Larry Gura lost the game when he lost his control midway through the fifth inning and walked in the tying and the go-ahead runs.

Until then, it was all long ball. Ken Singleton, wearing his deep orange "Go Deep" T-shirt, went deep on a Gura fast ball in the bottom of the first for the Orioles' first run, and first home run, of the season.

Clint Hurdle and John Wathan reciprocated in the top of the second, with back-to-back home runs that put the Royals ahead, 2-1. "Well, they weren't 500-footers," said Stone. "They only went into the second or third row. I'll trade two home runs for a win any day."

Last season, when Stone was 25-7, he had everything working for him, including a lot of luck; sometimes he won without his best pitch, and sometimes when he wasn't feeling his best, which he wasn't today.

Prior to the game, Stone, who had a 9.00 spring training ERA, was presented with a good-luck medal by a young boy named Ronnie, who has been befriended by the Orioles. A fan gave it to Stone last season, just before he beat the Yankees twice in eight days, and Stone gave it to Ronnie to take care of over the winter. "Stevie," he said, as he returned the medal to Stone, "I don't want to see you reverting."

Stone promised he wouldn't. But when Hal McRae led off the second with a single, and went to second on Doug DeCinces' error, the promise looked a bit shaky. Up stepped George Brett. Stone fell behind, 2-0, but came back with a fast ball away, a curve ball away and another curve down and in, striking out baseball's current threat to Ted Williams.

"Getting George Brett to miss two is like parting the Red Sea," Stone said. "I thought of asking for the ball but I forgot."

Gary Roenicke made the first sensational catch of the year, a running backhand grab against the left-field wall to add to the miracles, before Amos Otis singled to drive in McRae with the Royals' third and last run of the day.They led, 3-2.

But in the fifth inning, when he threw 33 of his 87 pitches, Gura decided that it was a beautiful day for a walk and issued four of them. The first was to Al Bumbry. Then, Rich Dauer hit a routine fly ball to Amos Otis, the Royals' reluctant left fielder who had been switched from center. Otis must have been distracted by the weather -- absolutely spectacular -- because he dropped the ball.

Gura must have been distracted by Otis, because he walked the next three men, Singleton, Murray and DeCinces, to put the Orioles ahead, 4-3. Rick Dempsey's home run an inning later made it 5-3.

By that time Stone was out of the game. When Hurdle, three for four with a home game run, led off the sixth with a single. Weaver decided that his flu-ridden pitcher had had enough; he had Stewart in the bullpen. Like Weaver says, "A guys gotta earn his living," which Stewart did, giving up two hits, and no runs, in four innings.

Still, he tried to make it interesting. U.L. Washington, who has forsaken his toothpick, started the ninth with an opposite-filed single, and Stewart walked rookie Ken Phelps. That brought up Willie Wilson. The last time most fans saw Wilson he was striking out for the 12th time in the 1980 World Series. Stewart struck him out.

Up stepped Brett, Stewart got two strikes on him, one of which was called while Brett stepped away from the plate.

"He stepped out, didn't he?" Stewart drawled. "He'd have to have a long bat to reach that one."

With the count 2-2, Stewart looked over at the dugout, where Weaver was waving madly. "Away from the plate, we don't want it in the right-field seats."

"I had two strikes on him and I said, 'All right.' Then, I said 'Uh oh. There's two runners on, in a two-run game.' George has a way of calming you down real quick. He's got that look in his eye: 'I know what you've got and I'm gonna go after it.'"

What Stewart had was a slider, and what Brett did was go after it, and what Bumbry did was catch it in center field for the last out of the first day of the Baltimore season.