The loudest cheers in baseball yesterday came from Kansas City. The Royals benefited most from the Cleveland victory here that forced a Yankee-Red Sox playoff today in Boston.

The Yankees were talking confidently about the 9-2 loss, echoing Coach Elston Howard's boast: "We'll get some runs on the board, we've got the best pitcher in baseball going for us and we beat (Mike) Torrez three times this year."

But the best pitcher in baseball, Ron Guidry, is not going into this playoff at his best. For his second straight start, Guidry will be asked to rescue the Yanks with three days rest instead of his usual four.

What excites the Royals is that if Guidry beats the Sox today - and he has pitched back-to-back two hitters in his last two starts against them - he probably will be limited to one American League playoff appearance instead of a certain two.

"It could be anybody, but unfortunately it's me," said Guidry. "But I'm ready. And I know how to pitch to those guys. The left-field wall? Every park's got a left-field wall."

During a season-long performance equaled by only a few pitchers in history, some of Guidry's best numbers have come against the Red Sox. In his next-to-last start against them, Sept. 9 in Fenway Park, Guidry allowed two hits in the first inning and nothing thereafter. The Yanks won, 7-0.

Six days later, in Yankee Stadium, the Sox mustered a double and a single off Guidry but still suffered a shutout, 4-0.

That was during Boston's semichoke stretch. Sox seem to have overcome all of that, although Torrez has a 6.16 earned-run average against the Yankees in 28 innings this season.

"Five to seven innings, that's all we want from him (Guidry)," said Yankee Manager Bob Lemon. "Just long enough for us to get our bullpen in there."

Of all Guidry's numbers this season, the 24-3 record, the 1.72 ERA, the 243 strikeouts, the one the Yanks hope is most significant is 14. That is the number of times Guidry has pitched after a Yankee loss - and won.

"The key is the first batter each inning," he said. "You get that guy out and it takes away the bunt possibilities, in most cases.

"If this team is tired - and I'd have to say we are - we have every right to be. We've been playing the best ball, coming from a long way back. We could have quit when we got so far behind, but we didn't.

"We're the defending champs and we've acted that way. And we'll act that way in Boston."

It was a 3-2 victory over Torrez here Sept. 16 that gave the Yankees their largest lead over the Red Sox, 3 1/2 games. They tried to coax one more inspired game from Catfish Hunter yesterday - and failed.

In truth, the Yanks went flat around the third inning, after the Indians bombed Hunter and reliever Dick Tidrow for six runs. Most of the hitters smung at the first recent pitch from Rick Waits, as though they could scarcely wait to get on to Boston.

And this playoff seems wonderfully appropriate. The teams with the two best records in all of baseball, the Yanks with the best pitcher in the game at the moment and the Red Sox with the best hitter, Jim Rice.

Each team has endured a stretch of dreadful injuries and found a way to recover. The Sox embarrassed a crippled Yankee team during one series early in the season; the Yanks returned the favor later.

After the loss yesterday, Lemon called a team meeting. It was not for the reason that might immediately leap to mind, though.

"The main thing was that I just wanted to tell them how much I've appreciated how they've gone about things since I've been here," said Lemon. "I know I won't have a chance to do that in Boston."

Since Lemon replaced Billy Martin July 25, the Yanks are 47-20. He was hired here for exactly the reason he was fired June 30 in Chicago - lack of bombast. He is a bright man who ego does not intrude on others, a Danny Ozark with a mind.

Lemon has kept remarkable control of himself during a season perhaps no other manager in baseball history has known. Fired from one team in midseason, he has a chance to win the pennant with another.

"I never take the game home with me," Lemon is fond of saying. "I always leave it in a bar."

There is no better bar talk than the Yanks vs. the Red Sox, two teams with such a memorable history against one another doing battle once again. In Kansas City, this is seen as a Royal way to end the season.