ST. PETERSBURG -- The American League Division Series no one saw coming is staring us in the face.

The Chicago White Sox and the Tampa Bay Rays, two unlikely division champions who finished a combined 54 games out of first place in 2007, will meet in the best-of-five ALDS beginning Thursday on 2:30 p.m. ET at Tropicana Field.

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The Sox clinched the American League East title by beating Minnesota, 1-0, in a tiebreaker Tuesday night in Chicago.

Tampa Bay had the worst record in baseball last season, losing 96 games, and was widely expected to finish below .500 this year. The Rays had never won more than 70 games or finished higher than fourth and had managed finishing out of the cellar just once. But the Rays went from worst to first in the AL East.

The White sox were supposed to be looking up at Detroit and Cleveland this season after finishing fourth with a 72-90 record last season. The Rays and White Sox lost 186 games between them last year.

And yet here they are, division champions and two of the most unlikely playoff party crashers you'll ever see. But that's about all they have in common:

• The Rays, with an average age of 27.4 years, are the fourth-youngest team in postseason history. The White Sox dominated by veterans, with an average age of 30.4.

• The Rays have some power, but are generally a line-drive hitting team. They get on base, run the bases well and pressure opposing staffs while relying on their starting pitching, bullpen and outstanding defense to get the job done.

• The White Sox, with eight players with 13 or more homers and six with 20 or more, including two of the all-time greats in Ken Griffey Jr. and Jim Thome, rely on power first and foremost.

• The Rays have a veteran closer who came out of retirement last year in 38-year-old Troy Percival. The White Sox give the ball to hard-throwing 27-year-old Bobby Jenks in save situations.

• Sox manager Ozzie Guillen and Rays manager Joe Maddon are about as different as Chicago is from St. Petersburg.

The Rays have been drawing comparisons to two of the most memorable turnaround teams in baseball history.

"I think [the Rays] mirror the [last-to-first] 1991 Braves in the sense that they have young pitching that looks, from afar, really talented, and barring any health issues they should be able to stay together for quite some time," said TBS analyst/Atlanta right-hander John Smoltz. "People in baseball who have played them could see this coming. You never know when a team is going to turn it around, you never know when a team is going to click. The longer [the Rays have] been in this position they don't feel like a last-to-first team anymore. We didn't when we were in position to win it. I think it's one of the best stories in baseball in a long time, the market, the lack of respect, the lack of wins they've had over the last decade or so."

TBS/New York Mets analyst Ron Darling said the Rays remind him of the '69 Mets.

"Because you're talking about, traditionally, a team that's almost been the laughing stock of the division," Darling said. "From top to bottom they've done an amazing job drafting and trading for veterans such as Cliff Floyd. The only thing iffy about it is they're so young these guys. The only issue is [what happens when] they get to that 240-250 innings pitched."

The White Sox added talents such as Griffey, Carlos Quentin, Alexei (The Cuban Missile) Ramirez and Orlando Cabrera to turn things around after last season's disappointing finish.

The Rays pick up of Jason Bartlett solidified an infield defense that had been a glaring weakness for Tampa Bay last season. Bartlett's contributions were such that he was voted the team's Most Valuable Player by the local chapter of the Baseball Writers' Association of America.

Rookie of the Year front-runner Evan Longoria gave the Rays needed power at third base, and combined with slugger Carlos Pena, gave the team a formidable one-two punch in the middle of the order.

Matt Garza, who came over from the Twins with Bartlett, has been huge. The right-hander gives the Rays another frontline starter behind Scott Kazmir and James Shields in a rotation that averaged 180-plus innings and 12.5 wins per man. Garza's arrival immediately lessened the relievers' workload and thus contributed to another big factor in Tampa Bay's turnaround -- the vastly improved bullpen.

In 2007 the Rays lost 52 games they led at some point. The bullpen ERA of 6.16 was the highest in baseball in 50 years.

This year the Tampa Bay bullpen shaved more than 2.5 runs off its ERA, as converted starter J.P. Howell and veterans Percival, Trever Miller and the recently acquired Chad Bradford helped shut down the late-inning merry-go-round opposing teams rode last year.

Both have overcame much to get this far, and now one will be advancing to the AL Championship Series.

One way or another, one unlikely run will continue.