After failing to reach the playoffs, Port was replaced by Yale University graduate Theo Epstein. Epstein, raised in Brookline, Massachusetts, and just 28 at the time of his hiring, became the youngest general manager in MLB history.
 

 

The Red Sox celebrate their clinching of the 2003 AL Wild Card with a victory over the Baltimore Orioles.

The 2003 team was known as the "Cowboy Up" team, a nickname derived from first baseman Kevin Millar's challenge to his teammates to show more determination.[42] In the 2003 American League Division Series, the Red Sox rallied from a 0–2 series deficit against the Athletics to win the best-of-five series. Derek Lowe returned to his former relief pitching role to save Game 5, a 4–3 victory. The team then faced the Yankees in the 2003 American League Championship Series. In Game 7, Boston led 5–2 in the eighth inning, but Pedro Martínez allowed three runs to tie the game. The Red Sox could not score off Mariano Rivera over the last three innings and eventually lost the game 6–5 when Yankee third baseman Aaron Boone hit a solo home run off of Tim Wakefield. Some placed the blame for the loss on manager Grady Little[43] for failing to remove starting pitcher Martínez in the 8th inning after some observers believe he began to show signs of tiring. Others credited Little with the team's successful season and dramatic come-from-behind victory in the ALDS.[citation needed] Nevertheless, Boston's management did not renew Little's contract, and hired former Philadelphia Phillies manager Terry Francona.
2004: World Series Championship

Main articles: 2004 Boston Red Sox season, 2004 American League Division Series, 2004 American League Championship Series, and

2004 World Series

During the 2003–04 offseason, the Red Sox acquired another ace pitcher, Curt Schilling, and a closer, Keith Foulke. Due to some midseason struggles with injuries, management shook up the team at the July 31 trading deadline as part of a four-team trade. The Red Sox traded the team's popular, yet oft-injured, shortstop Nomar Garciaparra and outfielder Matt Murton to the Chicago Cubs, and received first baseman Doug Mientkiewicz from the Minnesota Twins, and shortstop Orlando Cabrera from the Montreal Expos. In a separate transaction, the Red Sox acquired center fielder Dave Roberts from the Los Angeles Dodgers. Following the trades, the club won 22 out of 25 games and qualified for the playoffs as the AL Wild Card. Players and fans affectionately referred to the players as "the Idiots", a term coined by Damon and Millar during the playoff push to describe the team's eclectic roster and devil-may-care attitude toward their supposed "curse."

Boston began the postseason by sweeping the AL West champion Anaheim Angels in the ALDS. 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 year's ALCS in the ALCS against the Yankees. 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 on a two-run home run by Ortiz in the 12th inning, who 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 Schilling's right ankle bled throughout the game, famously making his sock appear bloody red. The Red Sox completed their historic comeback in game 7 with a 10-3 defeat of the Yankees. Ortiz, who had the game-winning RBIs in Games 4 and 5, was named ALCS Most Valuable Player. The Red Sox joined the 1942 Toronto Maple Leafs and 1975 New York Islanders as the only professional sports teams in history at the time to win a best-of-seven games series after being down three games to none. The 2009-10 Philadelphia Flyers would also accomplish the feat, coincidentally against the Boston Bruins.
 

 

The Commissioner's Trophy (2004 World Series)

The Red Sox swept the St. Louis Cardinals in the 2004 World Series. The Red Sox never trailed throughout the series; Mark Bellhorn's hit a game-winning home run off Pesky's Pole in game 1, and Schilling pitched another bloodied-sock victory in game 2, followed by similarly masterful pitching performances by Martinez and Derek Lowe. It was the Red Sox' first championship in 86 years. Manny Ramírez was named World Series MVP. To add a final, surreal touch to Boston's championship season, on the night of Game 4 a total lunar eclipse colored the moon red over Busch Stadium. The Red Sox earned many accolades from the sports media and throughout the nation for their incredible season, such as in December, when Sports Illustrated named the Boston Red Sox the 2004 Sportsmen of the Year.

2005-06

Main articles: 2005 Boston Red Sox season and 2006 Boston Red Sox season
The 2005 AL East would be decided on the last weekend of the season, with the Yankees coming to Fenway Park with a one-game lead in the standings. The Red Sox won two of the three games to finish the season with the same record as the Yankees, 95–67. However, a playoff was not needed, as the loser of such a playoff would still make the playoffs as a Wild Card team. As the Yankees had won the season series, they were awarded the division title, and the Red Sox competed in the playoffs as the Wild Card. Boston failed to defend their championship, and was swept in three games by the eventual 2005 World Series champion Chicago White Sox in the first round of the playoffs. After the season, general manager Theo Epstein resigned rather than accept a contract extension.
 

 

David Wells pitching for the Red Sox in 2006

In November 2005, the Red Sox announced the acquisition of pitcher Josh Beckett and third baseman Mike Lowell from the Florida Marlins, while sending several prospects including Hanley Ramírez to the Marlins. Fan-favorite Johnny Damon signed a four-year, $52 million deal with the rival Yankees, whom he had earlier vowed never to play for.[citation needed] The team filled the vacancy in center field by trading for Cleveland Indians center fielder Coco Crisp. However, Crisp fractured his left index finger in April and would end up missing over 50 games in 2006. Meanwhile, in January 2006, Epstein came to terms with the Red Sox and was once again named General Manager.

The revamped Red Sox infield, with third baseman Lowell joining new shortstop Álex González, second baseman Mark Loretta, and first baseman Kevin Youkilis (formerly the team's third baseman) was one of the best-fielding infields in baseball.[citation needed] The Red Sox committed the fewest errors in the American League in 2006, and set a major league record of 17 consecutive errorless games. One of the brightest spots of the 2006 season was the emergence of new closer Jonathan Papelbon, who became the first Red Sox rookie to be credited with 35 saves, earning an All-Star appearance. Also, David Ortiz broke Jimmie Foxx's single season Red Sox home run record by hitting 54 homers. However, Boston failed to make the playoffs after compiling a 9–21 record in the month of August due to injuries to catcher Jason Varitek, outfielderTrot Nixon, outfielder Manny Ramírez, pitcher Tim Wakefield, rookie pitcher Jon Lester (who was diagnosed with lymphoma), and pitcher Matt Clement. The Red Sox failed to make the playoffs as a result.

2007: World Series Championship

Main article: 2007 Boston Red Sox season
 

 

Pitchers (left–right) Josh Beckett, Jon Lester, Éric Gagné, pitching coach John Farrell andCurt Schilling, prior to a Red Sox game at Seattle in August 2007
 

 

2007 season final standing

Theo Epstein's first step toward restocking the team for 2007 was to pursue one of the most anticipated acquisitions in baseball history. On November 14, MLB announced that Boston had won the bid for the rights to negotiate a contract with Japanese Nippon Professional Baseball superstar pitcher Daisuke Matsuzaka. Boston placed a bid of $51.1 million to negotiate with Matsuzaka and completed a 6-year, $52 million contract after they were announced as the winning bid.