"I am not a Billyball player. I am a baseball player," said Rickey Henderson of the Oakland A's. "Everything is Billyball this and Billyball that. Everybody believes in Billyball."

In Oakland, it is the new national pastime.

"Frankly, I'm kind of surprised we haven't heard from the Billy Beer people," Roy Eisenhardt, the new president of the new Oakland A's, said today. "They probably haven't heard of us yet."

They will. The Oakland A's ended the month of April at 18-3, a league record for victories in the first month of the season. They also won their first 11 games of the season, another record. They lost one and then won another six.

"Why were we 17-1?" asked pitcher Steve McCatty. "Because we made a few mistakes. Otherwise, we would have been 18-0. The Angels came in and said, 'Ooh, your bubble is gonna burst.' And Maury Wills can't believe we're this good. Let 'em say it at the end of October, when we're still playing baseball and they're not."

How hot are they? Ask Billy Martin, who soaks his shoelaces every day before a game so his players won't be able to give him a hotfoot, a daily clubhouse ritual.

"During the streak, we had to burn someone every day to keep it going," said Henderson.

Who did they burn the day the streak ended? "It might have been the pitcher," Henderson said.

Undoubtedly, this is what pitcher Matt Keough had in mind when he said: "We are young and aggressive."

"We scrap," said McCatty.

Indeed, they do. Just ask the Angels, who scrapped with the A's twice Wednesday night over an allegedly corked bat and allegedly cheap shots. Martin, who has imbued the A's with confidence in themselves and in his hard-nosed, hard-ball, don't-mess-with-me ethic, led the way, putting a headlock on the biggest man on the field, catcher Ed Ott. "Didya see that, Tony, didya see?" he asked Armas later, a halo of a smile across his face. "You guys were beautiful. Just beautiful."

What's Billyball? "It's scratching, digging, fighting for every run you can get," said McCatty. "It's bunting, executing, not making mental errors. It's baseball."

Whatever you call it, the A's are doing it well. They are 18-3 largely because of a pitching staff with a league-leading ERA of 1.79. They have pitched four shutouts while giving up as many as four runs only three times. The Orioles may think they have the four Cys -- Old, Young, Present and Future -- but A's outfielder Armas disagrees. "Cy esta aqui," he said.

"That means, 'Cy is here," said McCatty, the translator.

The pitching staff is led by Mike Norris, this runner-up to Steve Stone in the 1980 Cy Young Award voting. "Michael Norris (5-0) can put a ballclub in a slump all by himself," said Keough, who isn't doing badly, either (4-0).

"He is in a league by himself with his screwball. He and (Rick) Langford pitched down the hitters, throwing breaking balls. Then (Brian) Kingman, McCatty and myself come back with the high fast ball. We get away with certain things because they (Norris and Langford) get the hitters out on their front foot and then we come back and throw the high fast ball.

"Mike, with his screwball, and me, are like our left-handed pitchers. Last year, Gene Mauch loaded up his order with right-handers against him because he thought lefties didn't have a chance."

This five-armed right-handed monster of a pitching staff completed 94 games last year (16 so far this year), obviating the need for a bullpen, a good thing, since the A's don't have one. Because each of the starters is so disimilar in style, it makes the staff difficult to solve during a series. "They're not going to be able to get used to just a sinker-, slider-type staff," Keough said.

Of course, some say the A's rely on spit as much as grit; an accusation they resolutely deny. "(Pitching coach) Art (Fowler) says we can't throw a spitter because it's unsanitary," McCatty explained.

The A's are leading the West Division by 4 1/2 games because of Armas, Henderson and Dwayne Murphy, "the best outfield in baseball," McCatty says. After 20 games, Armas leads the league with 22 RBI and five game-winning hits, and Henderson leads the league with runs scored (22) and stolen bases (16). Murphy is among the top 10 in three categories, runs (13), home runs (four) and RBI (14).

Yet, in Wednesday's 6-4 win over the Angeles, the hitting star was Tim Hosley, a man so anonymous that a caption in the Sport Illustrated cover story on the A's erroneously identified him as a clubhouse boy. Hosely didn't mind: "I was happy because I made SI."

Those who doubt the A's do so because of the number of anonymous journeymen, like Hosely, on the roster. "They can't accept that we can come back from losing 108 games two years ago," McCatty said. "Wherever Billy Martin goes, they say he's gonna screw up because he's a big tyrant . . . because it's Billy, they have to find something wrong."

It is no coincidence that in the middle of the Billyball theme song (to the tune of Charlie Brown), Martin has the key line: "Why's everybody always picking on me?"

Keough said: "Last year, they said he was wearing our arms out. This year they say he's letting seven guys carry the team."

Martin has imported several former Yankees, power hitter Cliff (Don't Touch My Thumb) Johnson and infielders Brian Doyle and Fred Stanley. They help make a good defensive infield.

But said Kingman, "Billy is the main factor. The talent has been here. This is the same team that went 54-108. . . But the manager changed every year. Billy's been in the World Series. With Billy and Art, when they talk, you can listen."

As Norris says, "Billyball is cute, but you've got to give accrediation where credit is due."

That being the case, it should be noted that if Martin has the A's playing Billyball, they are playing it with Charlie ballplayers. Charlie 0, the mule, may be dead and buried five blocks from Oakland Alameda County Stadium, but only stubborness precludes admitting former owner Finley's contribution to this team.

"That," said McCatty, "is the way to get yourself in trouble around here. I never said Charile was stupid. Cheap, eccentric, egocentric, yes. You can build the best car in the world and if you have the wrong person driving it, it won't go anywhere."

Of course, it was Finley who hired Martin to manage the A's. "Charlie couldn't get it out of us because we all hated Charlie," McCatty said. "When he had his heart opearation, it took eight hours -- 7 1/2 just to find his heart."

Then, one day last year, Finley sold the club to the Levi Strauss company. Keough says, "One day, we woke up and the wicked witch of the North had died and we were all the children of Oz."

Even the fans, who have come back in startling numbers (226,815 for nine dates this year, an increase of 168,200 over last), "hated Finley," said Craig Olsen, a 20-year old house painter. "You see those two scoreboards? They didn't work for two years. And the team didn't, either."

Since buying the club, Levi Strauss has increased the team payroll from $1.3 million in 1980 to $3.8 million in 1981; spent $1 million on stadium improvements ($250,000 alone on the scoreboard); upped the travel budget by $230,000. At the end of the Finley era, everything seemed to be on standby. Now, the A's go by charter.

A's such as Keough, who suffered through the indignity of 14 straight losses in 1979, are flying."Let me tell you something," he said. "Winning isn't everything. But losing stinks."