NEW YORK — More than one-quarter of the way through the 2007 season, there remains plenty of unknowns concerning the Red Sox.

But so far, this much is clear: they don’t stay down for long.

You have to go back a month, to April 23-24, to find the last time the Sox lost back-to-back games. Last night, after New York had won the opener of the three-game series Monday night, the Sox rebounded nicely with a 7-3 smackdown of the Yankees, ensuring that they didn’t get much traction for long.

By avoiding losing streaks, the Sox continue to pile up the victories with startling regularity: five of the last seven, eight of the last 11 and 12 of the last 16, ensuring that they seldom lose momentum.

The secret isn’t much of a secret at all.

“It comes down to getting quality starts,” said catcher Jason Varitek.

Starter Julian Tavarez set the tone with 5 2/3 innings, allowing just two runs and improving to 3-4 on his 34th birthday. Two of his three wins this season have come at the expense of the Yankees, who fell back to 10½ games out in the American League East.

“It was a team effort, what happened tonight,” said Tavarez. “Tonight, everything went right for me.”

Tavarez was the beneficiary of the some offensive backing even before he took the mound. Manny Ramirez crushed a pitch from Mike Mussina with Kevin Youkilis and David Ortiz aboard, giving the Sox a quick 3-0 cushion.

“We talk all the time about the (winning) formula — score first, then try to add on,” said manager Terry Francona. “That’s what we were able to do tonight.”

A solo homer from Mike Lowell, off the foul pole in left, opened the fourth and pushed the lead to 4-0.

Tavarez retired the first six hitters of the night in a row and 10 of the first 11. Not until Hideki Matsui lined a single to center with one out in the fourth did the Yanks claim a hit.

Weakened by a cold the last week, Tavarez started to show signs of fatigue in the middle innings. He wild-pitched a run home in the fourth and walked two in a row to fill the bases in the fifth, when the Yanks added another on a fielder’s choice.

But after issuing his fourth and final walk to Alex Rodriguez in the sixth, he erased the miscue with a double-play ball on his 106th and final pitch of the night.

Their lead cut in half, the Sox went about restoring some breathing room in the seventh off Mussina and the Yanks’ bullpen. Julio Lugo’s two-out single delivered Coco Crisp, and Youkilis, who earlier had extended his hitting streak to 15 games, hammered a double the other way to plate Lugo.

Lefty Mike Myers was brought in to get David Ortiz with Youkilis at second, but the strategy backfired when Ortiz laced a run-scoring double to right-center for the third run of the inning.

Boston’s Javy Lopez got the final out of the sixth and tossed a perfect seventh before Hideki Okajima stumbled some in the eighth, walking two, as the Yanks pieced together a run.

The run snapped Okajima’s run of 20 2/3 scoreless innings. Not since Opening Day in Kansas City, when Okajima’s first pitch in the big leagues was hit more than 400 feet by John Buck, had the left-hander been charged with a run.

“He was getting behind with his fastball, said Francona. “You’re not going to be perfect every inning, all year.”

Jonathan Papelbon, pitching in a non-save situation, was shaky in the ninth, too, walking two before freezing Derek Jeter on a called third strike.

But what remained was the Sox’ remarkable efficiency and refusal to let losing snowball on them.

“We play our game,” said Varitek. “We can’t worry about anyone but ourselves. It’s important we focus on ourselves, and not worry about the standings or what other teams are doing.”

If they continue winning games in bunches, it won’t matter what other teams are doing, anyway.

smcadam@projo.com