Boston began the postseason by sweeping the American League West champion 2004 Anaheim Angels season in the 2004 American League Division Series. In the third game of the series, David Ortiz hit a walk-off two-run homer in the 10th inning to win the game and the series to advance to a rematch of the previous years ALCS in the 2004 American League Championship Series against the 2004 New York Yankees season. The ALCS started very poorly for the Red Sox, as they lost the first three games (including a crushing 19-8 home loss in game 3). In Game 4, the Red Sox found themselves facing elimination, trailing 4–3 in the ninth with Mariano Rivera in to close for the Yankees. After Rivera issued a walk to Millar, Roberts came on to pinch run and promptly stole second base. He then scored on an RBI single by Bill Mueller, sending the game into extra innings. The Red Sox went on to win the game 6-4 on a two-run home run by Ortiz in the 12th inning. The odds were still very much against the Sox in the series, but Ortiz also made the walk-off hit in the 14th inning of Game 5. The comeback continued with a victory from an injured Schilling in Game 6. Three sutures being used to stabilize the tendon in Schillings right ankle bled throughout the game, famously making his sock appear bloody red. With it, Boston became the first team in MLB history to force a series deciding Game 7 after trailing 3-0 in games. The Red Sox completed their historic comeback in Game 7 with a 10–3 victory over the Yankees. Ortiz began the scoring with a two-run homer. Along with his game-winning runs batted in during games 4 and 5, he was named ALCS Most Valuable Player. The Red Sox joined the 1941–42 Toronto Maple Leafs season and 1974–75 New York Islanders season as the only Major professional sports leagues in the United States and Canada teams in history at the time to win a best-of-seven games series after being down 3–0. (The 2009–10 Philadelphia Flyers season and the 2013–14 Los Angeles Kings season would later accomplish the feat).

Who won a best-of-seven games series last after being down 3-0: Red Sox or New York Islanders?
Red Sox