BOSTON — The Yankees celebrated in the dugout as if they’d just clinched a playoff berth. In a way, they’ve done everything but. Hugging and shaking hands after a demoralizing fivegame sweep of the rival Red Sox, New York took a seasonhigh 6.5-game lead in the AL East with a 2–1 victory over Boston yesterday. The Yankees have never squandered a lead that large, and they hadn’t swept Boston in five games in more than half a century.

“A sweep in Boston?” winning pitcher Cory Lidle said, pausing before breaking out in a big smile. “Pretty awesome.”

After outscoring the Red Sox 47–25 in four games over three days and two early mornings, the Yankees rediscovered their pitching to win the sleepy series finale at Fenway Park.

“Everything went about as wrong as it could,” Red Sox manager Terry Francona said.”It’s not been a very good five days.”

Lidle (2–2) pitched six shutout innings in his third — and best — start since coming to New York at the trading deadline along with more-heralded slugger Bobby Abreu. With All-Star closer Mariano Rivera unavailable after pitching two innings to win Sunday night’s game — actually, it ended at 1:26 a.m.Yesterday — Kyle Farnsworth pitched the ninth for his second save in six tries.

Yankees manager Joe Torre shouted in the Yankees’ dugout and exchanged hearty handshakes with his coaches, then hugged his players as they came off the field.

Even they found it hard to believe.

“It was emotional,” Torre said. “When you’re sitting there, a manager’s dream is to have these guys, their attitude. The guys that didn’t play today — you had to be in the dugout to hear the support that they gave each other.”

There were a lot of regulars not playing for the Yankees, who rested center fielder Johnny Damon, catcher Jorge Posada, and first baseman Jason Giambi and used Derek Jeter at designated hitter. David Wells (2–3) coasted through the makeshift lineup for five innings before Abreu doubled in Melky Cabrera to break the scoreless tie.

Nick Green doubled and scored on a wild pitch in the eighth to make it 2–0. Wily Mo Pena homered off Scott Proctor for Boston’s only run.

It was 28 years ago that the Yankees came to Fenway in September with a four-game deficit and left tied for the division lead — a series remembered in baseball as the “Boston Massacre.” New York, which had trailed by as many as 14 games, won the AL East in a one-game playoff settled when Bucky Dent’s popup settled into the net above the Green Monster.

The Red Sox hadn’t been swept in a five-game series since the Cleveland Indians did it in 1954. The Yankees swept Boston in five games in New York in 1951 and at Fenway in ’43.

“It’s been an emotional weekend,” Red Sox second baseman Mark Loretta said. “It’s been physically challenging and emotionally challenging for both sides. It’s a little easier to take if you’re winning.”

Both teams left for the West Coast, with the Red Sox knowing that their best chance to make the playoffs is the wild card. They began the day four games behind the Chicago White Sox and three in back of the Minnesota Twins.

“We came into this series thinking we could make up ground (because) we were playing the team right in front of us,” Francona said. “We certainly didn’t put ourselves in a very good position. If we allow it to devastate us, then we weren’t good enough in the first place.”

Lidle allowed three hits and five walks to go with five strikeouts. Octavio Dotel, Mike Myers, and Proctor carried the shutout into the eighth.

Wells gave up two runs on six hits and a walk, striking out four before Green doubled and moved to third on Cabrera’s sacrifice bunt. Green scored to make it 2–0 when Keith Foulke’s third pitch was wild.

Red Sox outfielder Manny Ramirez left the game in the fifth inning with a cramp in his right hamstring. He had been the most productive player in the Red Sox lineup during the series, going 8-for-11 with two homers, seven RBIs and nine walks.

Notes: The 1933 Yankees led by six but finished seven behind Washington. … According to the Elias Sports Bureau, the last five-game sweep in the majors was Boston over Toronto at Fenway Park in 2002. … Red Sox SS Alex Gonzalez, who missed the previous two games with back spasms, was originally in the starting lineup but was scratched. … Jeter’s fourth-inning single was the 1,531st of his career, tying him with Bernie Williams and Lou Gehrig atop the Yankees’ all-time list.