BOSTON – You walked over the mystery puddle on the floor and into the claustrophobic, rickety visitors’ clubhouse where the Yankees change from their grays back into street clothes at Fenway. Nobody was celebrating. There was clutter and clanging, but no champagne. Nobody delivered a single bulletin board quote. Nobody promised the Red Sox were goners.

“They’re Jason, they’re Freddy Kruger,” GM Brian Cashman said. “They’re too good. Their organization is too good. In this game, you’re never in control.”

Cashman wouldn’t do it Saturday, wouldn’t bury Boston, because 2004 haunts him like a relentless poltergeist in a bad movie. You lose a three-game lead in the playoffs, it never goes away. You sleep on a frame of tenter-hooks for the rest of your professional life.

Joe Torre wouldn’t do it, either. He talked about momentum swings. He said people who believe this race is over, “they don’t know baseball very much, if that’s what they think.”

Jorge Posada said there was a lot of season left. Randy Johnson said he would have to start bearing down against the likes of Tampa Bay before anything is settled. One by one after their 13-5 victory, the Yankees offered praise and comfort to their vanquished foes.

The sentiment was wise, politically correct. But after three of the longest, clumsiest, most formless performances ever staged in this famous rivalry, the Yankees have clinched the five-game series in Boston and hold the pennant race by the throat, leading by a season-high 4games with 41 to play.

The Yanks would love to split the last two games this long weekend, sneak out of town, get to Sept. 4 when their schedule becomes considerably breezier. They didn’t expect it to be this easy. They were four games back on June 28, when they were 44-32 and looking way up at Boston. They’ve gone 29-16 since then, lined their depleted roster with top reserves. The battered Red Sox have played four games under .500 since then, looking now like a team that may well miss the playoffs.

The Yankees managed their one-sided victory Saturday mostly by standing around, watching Boston pitches get called for balls. Thirteen batters got free passes to first, which demonstrated both great patience at the plate and a remarkable lack of control by Josh Beckett and Jermaine Van Buren.

Other key moments in the game actually required some motion from the Bombers. There was, for example, a surly stroll to the mound by Torre in the fifth, when he ordered Johnson to stop the nonsense, to “empty your tank.”

Torre confronted Johnson after the lefty hit one batter, walked another and looked like he was about to implode facing the meat of the Boston lineup. Johnson then settled down, threw strikes, held Boston to one run that inning. The Yankees just need to hold the Red Sox to one run per inning, to nine runs per game, because this weekend they are averaging 13 runs per game.

“Our at-bats are unbelievable,” Posada said.

It is the mathematics of inflation, of lousy pitching. Johnson did better than most here. He made it through seven innings, gave up five runs. By the standards set in these games up here at Fenway, he was Koufax.

Posada knocked in four runs, smacked a bases-clearing, game-clinching triple in the sixth. He also stole a base, and the slo-mo catcher couldn’t remember when he ever had put together such an impressive show on the base paths. This was only Posada’s seventh career triple, his 13th stolen base. The weekend has been wacky enough to turn Posada into Maury Wills.

In the other clubhouse Saturday after the game, where the wackiness usually resides, the Red Sox looked beaten down, not their usual selves. The place was quiet, absent of music. David Ortiz sat at his locker, head down, giving sad interviews.

“This has never happened before, getting beaten up that bad,” Ortiz said. “It doesn’t matter what we do, it’s the wrong direction.”

You sometimes get a kind of twisted logic springing up around these pennant races. This game Saturday was supposed to be bigger for Boston than it was for the Yankees.

If it was big for the Red Sox, it loomed exactly as large for the Yanks. They are two rivals, chasing the same prize. This win was enormous for the Yanks, who might have been reeled right back into a tight race with one defeat, a two-game swing in the standings.

Instead, when the Bombers step into their clubhouse, change back into their grays, there is breathing space. Anything can happen, but you know that puddle will be waiting.