NEW YORK -- Joba Chamberlain jumped off the Yankee Stadium mound and launched into a pirouette, screaming and pumping his fist to punctuate the accomplishment of setting a new career high in strikeouts.

The moment was a nice one, but the Yankees were left wondering why their flame-throwing right-hander wasn't able to get rolling earlier.

Though Chamberlain struck out 12 batters and left to a standing ovation, the Yankees couldn't overcome his shaky first inning and suffered a 7-3 defeat to the Red Sox on a damp Tuesday evening at Yankee Stadium.

"I went out and didn't do what I was supposed to do," Chamberlain said. "They did a good job putting swings on it. This one's on me."

Johnny Damon belted a three-run homer off Red Sox starter Josh Beckett, but that was the sum total of New York's offensive production against the right-hander, as Boston took both games of the abbreviated two-game series. The Yankees have now lost all five of their games against the Red Sox this season.

"We couldn't be any worse," Yankees captain Derek Jeter said. "But we play them so many times. You've got to be able to move on."

As dominant as Chamberlain appeared toward the conclusion of his 5 2/3-inning start, he struggled mightily in the first inning, allowing hits to the first five batters he faced and watching four runs score, with Jason Bay slugging a three-run homer and David Ortiz drilling an RBI single.

It was questioned if Chamberlain had been fully unloading on his fastball in the first inning. Three of his first four pitches were clocked at 89 mph, and Chamberlain did not top 91 mph until after the home run to Bay, which prompted pitching coach Dave Eiland to visit the mound for a conference.

"Everything seemed to pick up a little bit," Girardi said. "His velocity picked up, and he got after it a little bit more. I don't think it was necessarily that he wasn't trying to get after it, but he was making better pitches."

"It looked to me like he wasn't letting it go," catcher Jose Molina said. "I don't know if he was feeling comfortable yet."

Immediately after the conference, Chamberlain amped up, pushing his velocity to 93 mph, and he continued to gain velocity until he was lifted with two outs in the sixth inning.

His last pitch was an 85-mph curveball that zipped past Jeff Bailey for Chamberlain's eighth straight strikeout and his ninth looking overall. It was set up by a 96-mph heater, his top speed for the night.

"I just started throwing strikes again," Chamberlain said. "You get strikeouts when you're trying not to -- just attacking the zone. I could throw anything for a strike at that point, so it was something I felt good about."

Though the crowd protested, Girardi said that it was not a difficult decision to lift the cruising Chamberlain after 108 pitches.

"No, because he hasn't really been over 90 pitches," Girardi said. "Physically, you can't do that to him. It's a tough spot if we let him keep going and he gets hurt. That's the real tough spot."

Damon brought New York to within one run in the third inning, turning on a Beckett offering and belting it into the second deck in right field for his sixth home run of the season and second in as many nights.

But that was all the Yankees could manage against Beckett, who evaded trouble in the sixth. The right-hander issued a one-out walk to Nick Swisher and allowed a Melky Cabrera ground-rule double to left -- a lucky break for Boston, since Swisher would have scored easily had the ball remained in play.

After summoning the grounds crew to work on the soggy mound, Beckett came back to strike out Ramiro Pena swinging and got Jose Molina to ground out to shortstop, ending the frame.

Leaving after facing one batter in the seventh, Beckett scattered 10 hits in holding the Yankees to three runs. He walked one and struck out five in his 108-pitch outing, the type that left Chamberlain wondering, "What if?"

"You're just thinking that you need to keep the team in the game," Chamberlain said. "It's a four-run lead and Josh is on the other side. You know it's going to be a battle all day. You've got to try and get deep in the game."

Needing to hold the game close in relief of Chamberlain, the Yankees' bullpen eventually faltered, as Girardi summoned six relievers to record the final 10 outs.

Jason Varitek added a sacrifice fly and Nick Green notched an RBI single in the eighth off Jonathan Albaladejo, and Mark Melancon walked the bases loaded to open the ninth before Dave Robertson issued a free pass to Bailey, forcing in Boston's seventh run.

Girardi said that he continues to believe in his embattled relievers, many of whom have had varying degrees of success over the past year-plus of the manager's tenure in the Bronx -- but there is little choice but to have faith.

With few answers to be found in ironing out that situation, the Yankees would instead like to solve the riddle of Chamberlain's soft first inning and hope for better results in five days.

"The positive part is, after the first inning, he shut down a pretty good lineup," Girardi said. "That's the positive part of tonight for Joba. Positives don't get you wins, though. You want to look at the good things and build on the good things, but you have to be ready to go."