Mike Napoli got a second shot at redemption and took advantage with a solo home run to straightaway center field in the 11th inning to give the Boston Red Sox a thrilling 8-7 victory over the rival New York Yankees in the rubber match of a three-game set at Fenway Park.
Napoli crushed a three-run homer earlier in the four-hour, 46-minute affair, but bounced into a double play with the bases loaded to end the eighth with the game tied.
It stayed 7-7 until Napoli sent Adam Warren's offering into the second row of seats in center field for Boston's ninth walk-off win.
Jonny Gomes added a solo homer and Shane Victorino knocked in a pair of runs for the AL East-leading Red Sox, who head into their four-game series against Tampa Bay holding a 1 1/2-game lead over the Rays.
The Yankees, who received three hits and a pair of RBI singles from Robinson Cano, have lost four of five to fall seven games back in the division race.
Warren (1-1) took the loss behind CC Sabathia, who turned in a forgettable performance on his 33rd birthday, yielding seven runs on nine hits and two walks over five-plus frames.
Sabathia's counterpart, Ryan Dempster, was in line for his first career win in seven starts against the Yankees but did not factor in the decision. Dempster was charged with five runs -- three earned -- on six hits and four walks in 5 1/3 innings of work.
Seven consecutive runs put the Red Sox in front by a 7-3 margin before the Yankees chipped away with a pair in the sixth via RBI singles from Brett Gardner and Cano.
New York got two more in the seventh to tie it, mostly thanks to Jose Iglesias' throwing error. The rookie third baseman's wild toss on Chris Stewart's sacrifice bunt attempt allowed Vernon Wells to score, and Luis Cruz followed with a run-scoring groundout.
The Yankees bullpen was terrific behind Sabathia, with the four relievers prior to Warren giving up just one hit over five scoreless frames.
Pedro Beato (1-0), with the help of Jarrod Saltalamacchia throwing out Eduardo Nunez on a steal attempt, anchored Boston's pen and picked up the victory.
A pair of errors -- one by Dempster and the other by Saltalamacchia trying to nab Ichiro Suzuki attempting to steal second -- led to a pair of New York runs in the first inning. Gardner scored on the catcher's errant throw, and Suzuki came around on Wells' one-out base hit to left field.
Cano made it 3-0 in favor of the Yankees with an RBI single in the second, but the Red Sox rallied for four runs in their third turn at the plate.
Jacoby Ellsbury started things with a double down the right-field line, and Dustin Pedroia put Boston on the board with a one-out single. After David Ortiz reached on a base hit, Napoli crushed a high, inside fastball onto Lansdowne St. beyond the left-field wall for a 4-3 Red Sox lead.
Boston added two more in the fourth. A hit batsman and two singles loaded the bases for Victorino, who chopped a base hit into left field to bring in Stephen Drew and Iglesias.
Gomes made it a 7-3 game in the fifth when he abused a Sabathia offering with a towering blast that hit midway up the light stand above the Green Monster.
Napoli has 12 career multi-home run games ... With their MLB-best 20th series win, the Red Sox already matched their 2012 total ... Boston is undefeated in its last nine completed home series (8-0-1) ... Sabathia is 0-2 with a 7.48 ERA in four career starts on his birthday ... Cano extended his hitting streak to 12 games ... Dempster came in 0-5 with a lofty 7.29 ERA in six career matchups with New York.