BOSTON — After the turmoil that hovered over the Red Sox the last week or so, culminating with the trade of disgruntled outfielder Manny Ramirez to the Los Angeles Dodgers, there was peace in the team’s clubhouse yesterday.

And while the renewed esprit de corps and team chemistry didn’t open the floodgates to a fireworks show from the offense last night, the Red Sox managed to snap a three-game losing streak on a two-out squibbed infield single by rookie Jed Lowrie that gave Boston a stirring walk-off 2-1, 12-inning win over the Athletics at Fenway Park.

The infield single delivered new hero Jason Bay, from third. Bay replaced Ramirez in left field, coming to the Sox from Pittsburgh in Thursday’s three-way trading-deadline deal.

Bay, who scored both Red Sox runs, lofted a towering two-out triple off the base of the Green Monster in left-center off former Red Sox’ Alan Embree for his first Boston hit.

After an intentional walk to J.D. Drew, Lowrie capped his interesting night by hitting Embree’s first pitch off the end of his bat. The ball bounced over Embree’s head and up the middle. It was fielded on the infield grass by Oakland shortstop Bobby Crosby on the move, but Crosby was unable to quickly get the ball out of his glove, and his off-balance throw was late and in the dirt.

Lowrie, whose sacrifice fly knocked in Bay in the second inning, easily crossed the bag safely with his second RBI of the night and was mobbed by his teammates. The hit atoned for his inability to come through with the bases full and two outs in the 10th, the at-bat ending on a 3-and-2 lineout to center.

“We got the win. That’s what it’s all about,” said Lowrie. “We wanted to set a tone going into the new month and I think we did that. We had a team meeting before the game and decided we’d move forward, start from here and see where it takes us. At the end of the season we’ll look back and say we either did it or we didn’t.”

Lowrie wasn’t about to claim he got good wood on his game-winner.

“It was my first at-bat against Embree. He threw me a good slider and I just hit it off the end of the bat. Sometimes it’s better to be lucky than good,” said Lowrie.

Manager Terry Francona felt relieved by the outcome in a game in which he used every available position player.

“We won a game we desperately tried to win,” said Francona. “Everybody gave everything they had.”

A key element in the winning run may have been overlooked. Drew was not being held on first because his run didn’t mean anything. First baseman Daric Barton was playing behind Drew, so on the pitch to Lowrie, Drew took off for second base, knowing the Athletics wouldn’t cover the bag.

And because he was running on the play, Crosby had no play for a force at second, which he would have had easily if Drew hadn’t been going. As a result Crosby’s only play was to first, a more difficult play he had to rush, and he couldn’t make it.

The ending set off a celebration on the field not to mention a loud outpouring of cheers from what remained of a sellout crowd of 37,832.

Not that the night didn’t have its share of unsettling moments, notably Hideki Okajima’s seventh blown save in eight chances and a right hip flexor injury aggravated by newly installed cleanup hitter Mike Lowell as he beat out an infield single in the 10th.

Okajima, called on to preserve Tim Wakefield’s 1-0 lead, surrendered a game-tying two-out opposite-field homer to Jack Cust in the eighth, tying the game at 1-1.

The ball bounced back on the field and originally was ruled in play, with Cust hustling to third for a triple as agitated Oakland manager Bob Geren rushed onto the field to protest that it should have been a homer. The umpires huddled and correctly agreed with Geren, giving Cust his 20th homer of the year.

It was the sixth time this season that the bullpen has squandered a lead for the hard-luck Wakefield.

Lowell, meanwhile, did not protest when he was led off the field by Francona and trainer Paul Lessard after feeling a strain in his right hip. There was no word on the seriousness of the injury immediately after the game, but the injury has been bothering Lowell for a while, Francona said.

The overall theme of the night, though, was positive.

The frustration of the last week, with Ramirez loudly voicing his displeasure with the organization resonating through a clubhouse and serving as a distraction as Boston lost five of the first six games on this homestand, had dissipated before the game.

All that was left for the Red Sox was to focus on the present and play the game the right way, messages Francona imparted in a 15-minute team meeting before batting practice yesterday.

They did just that. And while a laugher would have been a great way to celebrate the first post-Manny game, winning a tight one in extra innings may well have provided the emotional release that this team needed last night.

skrasner@projo.com