The defending World Series champions again looked disjointed while slipping to 9-12.
"I don't know if concerned is the right word," said ace Jon Lester, who took the loss. "I know everybody in here is busting their butt to do their best to get on a good run and put a full game together, whether it be pitching or defense or offense, whatever it may be. I hate saying it, but we've got a long ways to go and we're going to figure it out on both sides of the baseball and we'll be there -- we'll be fine."
Of late, the problem has been early deficits.
"For us to play with consistency, we need our starting rotation to lead us through that," said manager John Farrell. "Right now, we're not getting that."
The one constant Boston had until Tuesday was consistently strong outings from Lester.
But even that went away in this one, as Lester labored, giving up 11 hits and eight runs (only three of them earned) over 4 2/3 innings. The lefty threw a season-high 118 pitches.
Meanwhile, Ellsbury and Tanaka shared the spotlight well in leading the Yankees to their fourth win in five games against the Red Sox this season.
Ellsbury had a double, triple and two RBIs while making a nice sliding catch in left-center.
"He makes a big catch as well, and had a big hit to get the score to 7-2 after they had climbed a little bit closer to get it to 4-2," said Yankees manager Joe Girardi. "I thought he played extremely well."
Aside from back-to-back homers to David Ortiz and Mike Napoli, Tanaka fared well. The righty gave the Yankees 7 1/3 innings of two-run baseball, walking none and striking out seven.
"He has good stuff," said Napoli. "He uses four pitches at any time. He commands the strike zone. He's no different than a lot of pitchers in this league, but he definitely has good stuff. We couldn't really get anything going."
After getting a round of boos as he was introduced for his first at-bat at Fenway as a visitor, Ellsbury clocked the third pitch of the game high off the wall in center. A fan reached over and touched it, and it was ruled a triple.
"I just don't understand why he ended up on third with fan interference. Maybe I'll get the full explanation of it sometime, but no, that's part of the game," said Lester. "Sometimes you get fans running on the field, sometimes you get distractions, but you've got to bear down there and make a better pitch to [Derek] Jeter."
Jeter swiftly singled Ellsbury home, and the Yankees were out in front.
With Carlos Beltran at the plate, Jeter moved to second a passed ball and advanced to third on a throwing error by A.J. Pierzynski.
"I just tried to hurry and just made a bad throw," said Pierzynski. "It was a good read by Jeter. I was trying to make a play and I just short-hopped [Dustin Pedroia] and it went into center field."
Beltran then came through with an RBI single and the Red Sox faced a 2-0 deficit before taking their first swing.
Tanaka worked around a double by Pedroia and struck out Ortiz and Napoli.
There was big-time trouble for Lester in the third when the Yankees opened the inning with doubles by Alfonso Soriano, Mark Teixeira and Brian McCann, increasing their lead to 4-0.
Ortiz provided some life for the Red Sox in the bottom of the fourth when he unloaded for a prodigious shot into the center-field bleachers that probably traveled at least 430 feet. Napoli made it back-to-back homers, lacing one into the Monster Seats against Tanaka to make it 4-2.
"A couple of fastballs on the plate, we squared them up," said Farrell. "Many good pitchers, as you see, if you don't get them early, they're going to get a rhythm going. He was able to do that tonight. He threw, I thought, a high number of split fingers, which is a very good pitch for him, tough pitch to lift. More than anything, he pitched ahead in the count. That was the key tonight."
However, the momentum shifted right back to the Yankees in the fifth when the normally sure-handed Napoli dropped a liner by Brian Roberts that would have been the third out of the inning. The Yankees would go on to score four runs in that frame, all of them unearned, to take an 8-2 lead.
"Yeah, it was a little weird," said Napoli. "McCann was on first. I kind of lost it for a second. I thought I was on it. I need to make that play. That was a key situation in the game. We scored two runs. That would have been the final out, instead of them having a big inning. I didn't make the play."
The Red Sox know that they aren't playing winning baseball these days.
"We've given some extra outs," said Farrell. "At this level, when you do that, you're asking for trouble. It's something we continue to address, work at internally. There's not going to be wholesale changes made. We have to go out and execute with greater efficiency."