THE 1991 baseball season may not be remembered for dominant individual performances, but it certainly produced more than its share of dramatic team efforts - topped by a pair of unprecedented rags-to-riches stories in Minnesota and Atlanta.From the standpoint of batting and pitching, this year wasn't in the same league with other recent and not-so-recent campaigns. Indeed, for most of the season less attention was paid to what was happening on today's playing fields than to events of half a century ago. Newspapers ran daily charts of Joe DiMaggio's 56-game hitting streak and Ted Williams's drive to hit .400, and among the most publicized events of the year were the joint appearances of these two legends to commemorate that 1941 season. They were a tough act to follow. But even by today's standards 1991 was an off year for individual statistics. There were occasional big moments, to be sure - Rickey Henderson breaking Lou Brock's career base-stealing record, Nolan Ryan pitching an unprecedented seventh no-hitter, David Cone tying the National League record with 19 strikeouts. But in terms of season-long performance, batting averages were on the low side; no pitcher won more than 20 games; and there were no big human-interest stories li ke Cecil Fielder's triumphant 51-homer return from Japan last year. But then along came the Twins - and, even more so, the Braves - to turn the spotlight on the current season. Never before had a team risen from last place one year to a championship the next - and now not just one, but two. Add the other division winners - Toronto and Pittsburgh - and the result is a playoff picture about as different as it can be from the one most observers predicted when the season began in April. Then, the talk was of "dynasties," or at least repeat champions. The superstar-laden Oakland A's were riding the crest of three straight American League pennants and seemed likely to make it four. Boston's AL East defenders had spent lavishly in the free-agent market and were favored to win a second straight title. Cincinnati's world champions, after their four-game sweep of the A's in the World Series, looked like NL West repeaters. Ironically, it was NL East champion Pittsburgh that appeared the shakiest starting out. The Pirates had lost slugger Sid Bream to Atlanta via free agency, and also endured a much-publicized spring training squabble between superstar Barry Bonds and manager Jim Leyland. So of course they turned out to be the only repeaters, joined by Toronto in the AL East and the two Cinderella teams. The resulting league championship series now in progress assures an all-new cast for this year's World Series beginning Oct. 19. Minnesota, in fact, is the only one of the playoff teams that has appeared in the fall classic since the 1970s - and the Twins have only a handful of key players left from the club that won it all in 1987. Pittsburgh hasn't been in a World Series since the "We Are Family" triumph in 1979; Toronto has never made it; and the Braves haven't been there since 1958 when the franchise was still in Milwaukee. The Pirates, once they put their training camp squabbles behind them, pretty much ran away with their division. So, for that matter, did the Twins, though because of their last place, 29-games-behind finish a year earlier, it took a while for people to believe. The other two races went down to the wire. Toronto, benefitting from a big winter trade that produced slugger Joe Carter and defensive wizard Roberto Alomar, led in the AL East for most of the season. Boston finally got on track in August and made a late run, but the Blue Jays held on. And then there was the NL West, where Atlanta's rise from the ashes upstaged Minnesota's similar story and just about everything else. When the race heated up in late September, even the start of college football and publication of the much-ballyhooed sequel to "Gone With the Wind" weren't enough to take the minds of Atlanta fans off their beloved Braves. Their "Tomahawk Chop" rooting style became a national fad. The Braves had to do it the hard way, too. With more than a month to go, they lost star leadoff man and base-stealing king Otis Nixon when he was suspended for violating baseball's drug policy. Then they had to survive a down-to-the-wire battle with Los Angeles. Many thought the Dodgers, with their highly paid superstars and far greater experience under pressure, would come out on top. But on the final weekend, it was the young, inexperienced Atlanta Braves that rose to the occasion: After finishing last for three straight years, including a woeful 26 games behind in 1990, they earned a shot at giving the deep South its first-ever World Series. On the individual performance front, it wasn't a bumper year, but there were still some noteworthy achievements. Barry Bonds had another fine all-around season while leading the Pirates to their title, and is favored to capture a second straight National League Most Valuable Player Award. Things are less clear in the American League, where a close vote could develop between Fielder (44 homers, 133 RBIs) and Baltimore's Cal Ripken Jr. Ripken's figures weren't far behind (34 homers, 114 RBIs), and he out-h it Fielder by quite a bit at .323. He played his usual outstanding game at shortstop and also got a lot of attention by maintaining his assault on Lou Gehrig's all-time consecutive-game record.