What: The 2004 American League Championship Series between longtime rivals the New York Yankees and the Boston Red Sox. Here’s the back page of the New York Daily News, on the left after Game 3, and on the right after Game 7.

Why: Over the decades, what kept Yanks-Sox from standing alongside great team sports rivalries as Celtics-Lakers, Leafs-Habs, Bears-Pack, and Huskies-Lady Vols was the lack of postseason encounters. Before the introduction of the wild card, it was impossible for the Sox and Yanks to meet in the postseason. Since 1994, though, the bitter rivals have met three times in the ALCS. In 1999, the Yanks prevailed easily. In 2003, in a series marred by a brawl in which Sox pitcher Pedro Martinez faceplanted Yanks bench coach Don Zimmer, the Yankees squeaked out a 4-3 series victory. So in 2004, the Red Sox hired even-keeled manager Terry Francona, and supplemented Martinez with a second ace, Yankee-killer Curt Schilling. The Yanks countered by stealing reigning MVP Alex Rodriguez from his Sox suitors. In the ALCS rematch, it looked like the Sox would wait at least one more year to shake the Curse of the Bambino, as the Yanks ran off to an insurmountable 3-0 series lead, destroying them 19-8 in Game 3. This looked even less surmountable when, in Game 4, the Sox were down a run in the bottom of the ninth, with sandman Mariano Rivera on the mound. And then Dave Roberts stole second. Then Bill Mueller drove him home to tie it. Then David Ortiz bombed one out in the 11th to win it. Then he won the next one in the 14th. Then Schilling took his team name literally, bleeding through his sock from a ruptured ankle tendon. Then Rodriguez slapped Bronson Arroyo, sealing the Boston win and A-Rod’s lifelong reputation problems. But all this did was tie the series, to be broken in Yankee Stadium. Surely the Yanks couldn’t lose there, not against the team they had kept down for 86 years, right? Yes they could, Boston, yes they could.

Impact: One pro forma sweep of St. Louis later, the Red Sox reversed the Curse. Hardly a championship-starved city (the Celtics had won 16, the Patriots 3, and the Bruins 5), Boston greeted the Sox as if they’d never seen a victory before, parading the team down the dirty water of the Charles River. (Curse reversal was contagious: After its own half century drought, the other Sox would join that company the next year. The Cubs? Not so much.) The win also solidified the misguided expansion of “Red Sox Nation,” which turned into one of the most obnoxious fan bases on the planet. But don’t fret, Red Sox fans. In this regard, you will always be second to the Yankees.

Personal Connection: Like with the McGwire-Sosa home run chase of 1998, the 2004 championship threatens to be swallowed by its stars’ connection to steroids. At least seven of the series’ marquee names (Yankees players Rodriguez, Jason Giambi, Gary Sheffield, and Kevin Brown, and Sox players Ortiz, Arroyo, and Manny Ramirez) have been linked to performance enhancing drugs. And there’s the sad reality that a postseason series between the two highest-salaried teams is hardly shocking given baseball’s economic insanity. All this caused me to debate whether to give this series the spotlight. For about a tenth of a second. The fact is that two great teams, both playing with significant unfair advantages, clashed in the most riveting games I’ve seen as they occurred. You can asterisk records, but you can’t delete memories.

Other Contenders: the 1987 Eastern Conference Finals between the Boston Celtics and the Detroit Pistons, featuring Larry Bird’s famous steal; the 1991 World Series between the Minnesota Twins and the Atlanta Braves, with five games decided by one run, three in extra innings; the 1993 Eastern Conference Finals between the Chicago Bulls and the New York Knicks, the most bruising NBA series ever played; the entire heart-stopping 2003 NHL postseason, featuring a slew of shocking upsets and 38 overtimes; the 2003 Western Conference Semifinal between the Los Angeles Lakers and the San Antonio Spurs, redefining the phrase “last-second heroics”; the 2009 Eastern Conference Semifinal between the Pittsburgh Penguins and the Washington Capitals, in which Ovechkin and Crosby scored hat tricks in the same game.