Down 6-0, Colorado came back with two runs in the sixth, and Matt Holliday's three-run homer in the seventh on Hideki Okajima's first pitch cut the Red Sox lead to 6-5.
But then Ellsbury lofted an RBI double down the right-field line off Brian Fuentes in the eighth that just eluded Brad Hawpe's attempt at a sliding,
backhand catch, and Pedroia followed with a two-run double to right that put Boston back in front by four runs.
Jason Varitek added a sacrifice fly in the ninth.
On October 27, three years ago at old Busch Stadium, the Red Sox completed a sweep of St. Louis for their World Series title in 86 years.
Lucky number seven
Having won seven straight Series games for the first time in franchise history, Boston will try for its seventh championship Sunday.
Jon Lester starts for the Red Sox against Aaron Cook in a matchup of pitchers who made it back to the majors after major medical problems.
Every team that has taken a 3-0 World Series lead has gone on to win.
If the Rockies are the National League's best, the senior circuit has a lot of catching up to do.
Maybe it is the rust of a record eight-day layoff for the Rockies, or maybe the Red Sox really are a league above.
Colorado has been outscored 25-7, has only 22 hits and is batting just .222.
Boston's batters were bruisers in the pinball parlor of Coors Field, and hitting .352 in the Series with 16 doubles.
The game took 4 hours, 19 minutes, the longest nine-inning game in Series history.
Colorado was the talk of baseball with 21 wins in 22 games coming into the Series.
But the Rockies have gone into reverse, looking more like the fourth-place team they were in mid-September.
Boston, meanwhile, has won six straight since falling behind Cleveland 3-1 in the AL championship series.
While the Yankees owned the 20th century, the Red Sox are one win from becoming the first team to win two titles in the 21st.
Boston's Terry Francona, the first manager to start 7-0 in Series history, made all the right moves.
Ellsbury, who hit ninth in the opener and No. 8 in Game 2, moved to the top of the order and became only the third rookie with four hits in a Series game, following Freddie Lindstrom in 1924 and Joe Garagiola in 1946.
David Ortiz, kept in the lineup despite the loss of the designated hitter in the NL city, doubled in the first run and flawlessly handled both his chances at first base before Kevin Youkilis replaced him in the bottom of the sixth.
|Javier Lopez with what appears to be a painful|
pitching style [GALLO/GETTY]
Colorado's Clint Hurdle also made some moves.
He benched center fielder Willy Taveras, started Cory Sullivan in center, moved Kaz Matsui to leadoff and batted Troy Tulowitzki second.
Silencing the crowd
Decked out in Rockies purple and bundled in blankets and ski caps, fans at Coors Field were noisy for the first World Series game in Denver's history.
But Fogg allowed 12 of 19 batters to reach, and the crowd of 49,983 quickly became quiet.
Matsuzaka, the first Japanese pitcher to win a World Series game, was worth every penny the Red Sox spent to lure him last winter.
He pitched shutout ball into the sixth and wound up allowing two runs and three hits in 5 1-3 innings.
Matsuzaka left after consecutive walks with one out in the sixth, and Javier Lopez allowed consecutive RBI singles to Hawpe and Yorvit Torrealba that made it 6-2.
Mike Timlin relieved, and pinch-hitter Ryan Spillborghs flied to Ellsbury, who was just in front of the center-field wall.
Jeff Baker, another pinch hitter, then hit a liner that shortstop Julio Lugo caught with a leaping grab.
Holliday had Rockies fans thinking comeback with his home run into the Rockpile, which ended a streak of 17 1-3 scoreless innings in the postseason for Okajima and closer Jonathan Papelbon.
Todd Helton followed with a single, but Okajima recovered to strike out Garrett Atkins and Hawpe, then retired Torrealba on a comebacker.
Colorado put two on with two outs in the eighth off Manny Delcarmen.
Papelbon relieved and Holliday hit a drive to left that died and was caught easily by Manny Ramirez.
Papelbon then closed out Colorado in the ninth for his second save of the Series.
Matsui singled on the first pitch by Dice-K, his former teammate on the Seibu Lions, but Tulowitzki struck out and slammed his bat in the dirt.
Matsuzaka then stabbed Holliday's comebacker, and Matsui got caught in a rundown.
By the time the Rockies finally scored, they were down 6-0.