In a game of gifts and blunders, on a night of mist and mud, in a contest full to the brim with what might have been, Pittsburgh beat Baltimore, 3-2, in the ninth inning tonight to even the World Series at a game apiece.

The Bucs were in their elements tonight -- steady rain in the late innings, mire all over Memorial Stadium, and unlikely heroes coming forth as the witching hour approached.

In a typical Pirate marathon, the sort they have endured and prospered in all season, ancient catcher Manny Sanguillen drove in the winning run with a pinch-hit single off Oriole loser Don Stanhouse with two out in the top of the ninth.

As befitted a game of snafus, the man who scored the winning run -- another slow catcher, Ed Ott -- reached base when his two-hop grounder bounced off the chest of a second baseman -- Billy Smith -- who probably should not have been in the game.

Ott took second as feisty Phil Garner drew a walk off the interminably laborious Stanhouse.

Seldom has there been a more unlikely, yet appropriate, matchup -- Stanhouse, the nibbling bad-ball pitcher, against the 35-year-old Sanguillen, the king of the bad-ball hitters.

Stanhouse, ahead in the count, 1-2, fed Sanguillen the type of perfect two-inches-off-the-low-outside-corner slider that is the cornerstone of his livelihood. And Sanguillen slapped it on one sharp hop to Oriole right fielder Ken Singleton.

Ott should have been out at the plate. He was a step and a half around third as Singleton's 225-foot peg headed plateward.

Perhaps, had cutoff man Eddie Murray never touched the ball, Ott would have been an easy out with catcher Rick Dempsey scampering 10 feet or so up the thrid base line to grab the throw before the lumbering "Otter" ever arrived.

And, perhaps, Singleton's too-low throw would have died in that wet grass; would have taken two slow hops and arrived too late.

Or, perhaps, that throw would have been too far up the line and Ott would have scored.

All that is sure is-that Murray cut off the throw, whirled and fired to Dempsey, who was too late blocking the plate and making the tag.

In this 3-hour 13-minute marathon of mistakes that final unresolvable confusion is probably the fitting grace note.

"Hard to say . . . can't be sure," muttered Manager Earl Weaver.

What he did know was that Ott should have been back in the dugout, not out on second base.

"We had Ott's ground ball. We did not field it," said Weaver. "What was it called? Hit or error?"

It was called a hit. The error almost certainly should have gone to Weaver himself. He called in Stanhouse with a man on first and one out in the top of the ninth. Ten years ago, before the designated hitter made managers learn a new kind of baseball, Weaver would not have thought twice. He would have looked at his lineup card, seen that Stanhouse was batting in the No. 2 spot and he would have been made a fundamental switch.

Most likely, as managers have been doing for a century, he would have put the surer glove of Rich Dauer at second at the same time Stanhouse entered -- with Dauer hitting second and the pitcher eighth.

Making the move even more logical was that Dauer would have been the fourth batter in the bottom of the ninth and the pitcher ninth, since Smith had just made the last out of the previous inning.

It's complicated, but it's also fundamental. And Weaver, accustomed to pitchers never batting, just forgot.

There were an abundance of other misfortunes tonight that overshadowed the conventional highlights of a Series game. True, Murray knocked in both Oriole runs with a titanic 450 foot-homer in the second inning and an RBI double to the fence in left in the sixth -- both off Buc starter Bert Blyleven.

And the Pirates, now headed home for three straight games on the speedy Astro Turf that they love and that the Orioles hate, scored a pair of runs in the second off Jim Palmer. Consecutive leadoff singles by Willie Stargell, John Milner and Bill Madlock scored one run and Ott's sacrifice fly brought home the other.

But the unique dimension tonight was all the runs that were left unscored and all the plays that were left unmade.

The premier muff injudgment belonged to the Orioles in the bottom of the eighth, score 2-2, when the Pirates did everything in their power to give the game away.

The Birds already had been given countless gifts. Omar Moreno got himself trapped off first base by 90 feet on a foul pop that became a double play. Blyleven, failing to hustle, bunted into another double play on an attempted sacrifice. In addition, Moreno fanned with the bases loaded once, and right fielder Dave Parker, making a one-handed swipe at an easy fly, batted it to earth for a two-base error.

But in that Oriole eighth, the granddaddy of bonuses arrived. After Murray, reaching base for the seventh time in eight Series at-bats, dumped a broken bat single into center, Doug DeCinces, who earlier had made his third error of the Series, laid down an awful sacrifice bunt that went right back to the mound.

Buc pitcher Don Robinson had Murray dead at second, but his burning throw was slightly behind shortstop Tim Foli. And Fole flat dropped it for the Pirates' fifth error in two games, not counting at lease give other flubs that were unpunished, or unpunishable, by the scorer.

With two out, it was time for another bunt, but batter John Lowenstein got smart and tried to slap a grounder past the charging third baseman, Madlock.

"I chose for him to win it for us right there," said Weaver, implying that the decision had been his. "He's my man, he's won me a lot of games this year. When you gamble and shoot craps, sometimes you lose."

The Birds lost. Their gamble played right into the hands of a Pirate gambit. Buc shortstop Foli was racing to third to try for a force out there after Madlock fielded the ball. It is a standard, if risky variation on normal bunt defense.

Lowenstein's grounder was right at Foli -- a perfect double play ball. Had Murray not stopped in the base path, avoiding a tag, it might have become an around-the-horn triple play. As it was, after getting the short-to-second force, Pittsburgh wisely chose to run down the hung up Murray between second and third.

This full-throated throng of 53,379, which had smelled a victory for a whopping 2-0 edge just seconds before, sensed the ominous foreboding of a team that has made one blunder too many.

The Orioles might have known that this was a Pirate evening. Unless the Bucs play until the edge of a.m., unless the rain is falling and conditions are miserable, unless the parade of relief pitchers seems endless. The Family does not function best.

"Anything we do is going to be for (Roberto) Clemente," said Sanguillen, speaking of his former teammate who died in a plane crash in 1972.

Teased from his somber mood by Pirate teammates, citing his season-long total of just four RBI in 74 atbats, Sanguillen retaliated, "I think you wrong. I drive five."

Sorry, Sangy. Only four. Five tonight.

All the undercurrents existed tonight for a long, thrilling and deeply strategic Series. O's catcher Rick Dempsey gunned down two more Pirate base thieves, Madlock and Matt (the Scat) Alexander. For Alexander, a pinch runner by trade, it was the first time he had been thrown out this season.

"We'll keep runnin'," said Manager Chuck Tanner, whose club stole 180 bases this season, but none so far in the Series. "And Dempsey'll keep throwin'. This, Series is going to be a long dogfight between two great clubs. You can see it already."

If the Pirates are in search of speed, then the Birds are desperate for more power after scoring just two runs in their last 17 innings.

"I'm going to put in a call for Dr. Long Ball tomarrow," said Weaver.

The Orioles' final thought of this evening will not be of masterful Pirate reliever Kent Tekulve mowing down three Birds in the ninth to save the victory for Robinson, who so easily could have been the loser.

Nor will it be of the venerable and beloved Sanguillen, who hit .379 with 11 hits in the '71 Series between these teams, coming off the absolute extremity of the bench to flick a winning hit to the opposite field.

They will dream of throws from right field. In the Oriole sixth, Murray, after his game-tying double, stood at third with one out. Lowenstein, that other protagonist of the evening, stroked a liner to right field -- to the same spot, in fact, from which Singleton has to make his throw.

Parker's peg to the plate was true. No one dared to cut it off. And Murray was out by 10 feet.

Singleton's throw never got there in one piece.

And every Oriole, as they wing their way to Pittsburgh, will wonder what would have happened if it had.