The Milwaukee Brewers did little of what they're expected to tonight, and in the end it was a man who wasn't even supposed to play who put them within one day's grasp of their first American League division championship.

The unlikeliest Brewer hero was Ned Yost, a seldom-used reserve catcher who hit a three-run homer in the ninth inning to break a tie and give the Brewers their second straight victory over the Red Sox, 6-3.

Coupled with the Baltimore Orioles' 3-2 loss in Detroit, which flashed on the scoreboard here just before the Brewers took their final turn at bat, the victory drops Milwaukee's magic number to two.

Any combination of Brewers victories and Orioles losses adding up to two would seal the East Division crown for Milwaukee. If that happens Thursday, it would render meaningless the vaunted season-ending showdown in Baltimore between the two contending teams.

But tonight the story was of a fellow who regards warming up the pitchers as his daily important contribution to the powerhouse Brewers. Yost had only 95 at bats this year, playing behind Ted Simmons, and he was an eighth-inning defensive replacement tonight only because Simmons had given way to a pinch runner the inning before.

But in the ninth, tied, 3-3, the Brewers got a man to first with one out when relief pitcher Mark Clear walked speedster Paul Molitor. Molitor stole second base (his 41st steal) while Robin Yount was striking out, which brought up Cecil Cooper with two out.

Veteran Sal Bando, an assistant to the Brewers' general manager, then advised Yost, "You're gonna have to win it for us, because I'm sure they're going to walk Cooper."

That put the second-string catcher in a dither, because he was so sure he wouldn't be asked to hit on this crucial road series he hadn't even bothered to bring his bats. He raced around the dugout, stripping off his catcher's gear and looking for a weapon, and in the end settled for one of teammate Charlie Moore's bats.

He took the first pitch from Clear, a curve, for a ball. Clear's next offering was a fast ball and Yost clobbered it into the screen atop the left field wall for the game-deciding three runs.

It was Yost's first homer of the year and his fourth in the majors. He's been with the Brewers 2 1/2 years, but never has been used regularly. He was batting .274 coming into tonight's game.

Manager Harvey Kuenn said he never considered pinch hitting for Yost, even though he had left-handed slugger Roy Howell on the bench.

The problem was that if he'd brought on Howell, Kuenn said, the Red Sox would have countered with left-hander Tom Burgmeier, and Kuenn would have had to go to his third-string catcher, Moore, who was already occupied playing right field.

So it was up to Yost, who said with characteristic modesty, "I was in a daze when I went around the bases. I was so thrilled I couldn't think of anything."

Brewer reliever Bob McClure (12-7), mopping up for Don Sutton, who gave up three runs in seven innings, retired the Red Sox to seal the win. After the final out, Yost raced out to shake his pitcher's hand and instead found himself mobbed by his teammates.

It was not a typical Brewers' victory. There was little in the way of hitting fireworks on a cold and breezy night with the wind whooshing in from center field.

The Red Sox took a 2-0 lead in the first on Jim Rice's homer over the green monster in left field.

The Brewers pecked back at Boston starter John Tudor with a run on Don Money's homer in the second, then single tallies in the third and fifth that resulted from one clean single, one infield single, Simmons' blooped nubber of a single and a walk, hardly the normal trappings of the powerhouse Brewers. But the minirallies put them ahead, 3-2.

The Red Sox retied it when Gary Allenson cracked a leadoff homer in the seventh, his second in two days.

Then, in the ninth, the Orioles' ninth-inning demise became public on the scoreboard in left field. A hush seemed to settle over the 18,390 Fenway Park fans, who had been staging riotous brawls throughout the evening for reasons interminable.

With a stroke of his borrowed bat, Yost silenced the silence.

The Brewers were stunned by their sudden good fortune. "Coming in to Boston we knew the magic number was six," said General Manager Harry Dalton. "To end it, we'd have to sweep six of six possibles. So far, we've taken four out of four."

And in the process, they've anointed a new hero. "We really haven't seen enough of Yost to know what he can do in the majors," said Dalton. "Tonight, he bought himself a little time."