Perhaps no test in American sport is so purely a question of surviving pressure as the World Series.

The tension builds not for hours, but for days, as the sins of yesterday are visited on today -- all under the eyes of tens of millions of long-memoried television viewers.

The possibility of daily redemption is only the other side of the potential for redoubled disgrace.

Those with doubts on this point are referred to the Pittsburgh Pirates, a baseball team that is suffering from a recurring nightmare called the Baltimore Orioles.

During four consecutive Series days, the Pittsburghers have batted an outlandish .329 as a team, outhitting Baltimore by 63 points.

Yet again today, despite 17 Pirate hits, it was Baltimore that won, 9-6, here in somnolent Three Rivers Stadium. And it is these Pirates -- trailing three games to one -- who face possible elimination here when the Bucs and Birds meet a fifth time Sunday.

Pressure shows itself in many baseball manifestations: an instant's hesitation, a pause that betrays fear or simply an inability to achieve that sense of relaxed concentration without which a professional athlete becomes a civilian.

Ask Omar Moreno of Pittsburgh, who has stranded 11 runners on base, who has been picked off first, who has been doubled off first base on a foul pop by 100 feet.

Ask the Buc runners who have been trapped between bases with no helicopter to rescue them: Dave Parker hung up off first, Phil Garner off second and Ed Ott off third.

And, above all, ask every member of that Pittsburgh defense that has made eight errors in four games.

Perhaps baseball team uniforms should come equipped with arrows that point either up or down, because, at the highest level of tension and competition, every team surely is headed in one direction or the other.

No happy medium exists, no possibility of a bland consistency -- not in such a short and harsh statistical sampling.

One final time, ask the Pirates, who gave Baltimore nine outs in the very first inning of the first Series games, what it is like to try to stop an emotional snowball from rolling.

That sense of psychic slippage, a tremble in the equilibrium, shows itself in devious ways.

At noon today, just one hour before game time, Pittsburgh Manager huck Tanner, dressed head-to-toe in his canary-yellow Pirate uniform and spikes, was tiptoeing through the parking lot toward his Mercedes Benz.

He had left the lights on and the battery was dead.

Tanner got his car restarted and recharged, but it is a harder task when the dead energy cell is at the heart of a 25-man team.

Without question, the most crushing focus of tension in this peripatetic pressure cooker is located in the manager's seat.

Other players can have their momentary lapses of attention.

For instance, when Baltimore catcher Rick Dempsey raced to the mound after the final Pittsburgher struck out today, the little banty rooster backstop threw his arms around his pitcher's waist and started to lift.

Only then did Dempsey remember that Tim Stoddard is 6 feet 5 and weighs 250 pounds.

For managers, however, it is forbidden that they look foolish in a World Series. For fear that the tremor in the hands will infect their entire club with the shakes, managers, by ancient tradition, must defend their manuevers with a catechistical certainty.

That has given this Series an extra dimension of special pressure at the top, because both bosses -- Tanner and the O's Earl Weaver -- are theoreticians with a renegade stamp, inconoclasts in a stodgy profession.

For baseball's ancient book -- the unwritten but universally understood dogmas of proper percentage play -- both have open contempt.

"I have never read the book," says Weaver, loftily. "Ido what seems logical to me."

In this Series, he repeatedly has spit in the eye of the sacred sacrifice bunt -- even the hallowed two-on, none-out bunt. He has let pitchers bat for themselves, and even swing at 3-0 pitches.

For these transgressions, he has suffered baseball's equivalent of the public lashing -- the second-guess. "Where Weaver Went Wrong," blared the back page banner headline today in the largest circulation daily newspaper in America.

Tanner has lived a baseball life of boldness, believeing more than any manager in history that hell-bent aggression will crack an opponent's will.

Once, a Tanner team stole 341 bases, using the base theft as a form of personal insult. In another city, he broke a century of tradition by using just three starting pitchers with an unheard-of two days' rest between assignments.

And now, in yet another city, he has used relief pitchers with an abandon never seen before -- waving in his big three of Kent Tekulve, Enrique Romo and Grant Jackson 250 times in one season.

Today, as he has done earlier in the season, Tanner frittered away another vital lead while his bullpen -- vastly more rested than it has been since March -- was left to rust.

The Pirate manager left a 22-year old hurler, who had a .500 record this year, on the mound in the eighth inning to protect a three-run lead. By the time Tanner could get Tekulve warm and into the game, the bases were loaded.

Everybody scored. The Orioles won.

The Pirates, a daring team that won more games than any Pittsburgh outfit since 1909, have totally abandoned their style -- under tactical pressure from Baltimore.