"Once I saw Manny hit the three-run homer, I knew it was going to be a good night," Tavarez said.
One night after losing the series opener, Boston re-established a 10½-game cushion over the Yankees. The Red Sox have won eight of 10 meetings starting Sept. 17 last year and are 9-3 against New York since a five-game sweep at Fenway Park in August sent the Yankees on the way to their ninth straight division title.
"He's waiting out this series, I think," spokesman Howard Rubenstein said.
New York (20-24), which managed only four hits, has lost its past three series and eight of 12 games overall.
"You really have to think in terms of winning series, and certainly the pressure is on us to do that tomorrow," Yankees manager Joe Torre said.
"He went in late and threw an elbow, but it's no big deal," Pedroia said. "I know now that when he's going in, my arm slot drops to the floor. Some people play like that, and some people come in with hard, clean slides."
Mussina (2-3) lost his second start in a row following consecutive wins. He was booed by the crowd of 54,739 and ended the night with a 6.52 ERA in six starts this year. The right-hander, who fell to 19-15 against Boston, was tagged for seven runs and 10 hits in 6 2/3 innings.
"Nothing this year has been very consistent for me. Nothing has been routine," Mussina said. "It's almost June and I don't feel like I've done anything as far as contributing, up to this point."
Staked to a 4-0 lead, Tavarez (3-4) walked four but held New York to two runs and three hits over 5 2/3 innings in beating the Yankees for the second time this season.
"He deserved to win," Derek Jeter said. "We didn't have too many good swings against him."
The previous major league pitcher to start and win on his birthday was Derek Lowe of the Los Angeles Dodgers on June 1 last year against Philadelphia.
Tavarez said he didn't feel strong at all on the mound because he's been sick the past three days. Still, he got the job done.
"Over and over, he's given us quality starts, and that's key with this ballclub," catcher Jason Varitek said.
That snapped Okajima's streak of 20 2/3 scoreless innings, the longest by a Boston left-hander since Bruce Hurst's shutout stretch of 21 2/3 innings in May 1987.
Jonathan Papelbon walked two in the ninth, then retired his next three batters, including two strikeouts. He fanned Jeter to end it.
Trailing 4-1, the Yankees loaded the bases with one out in the fifth on a double and two walks. Tavarez was up to the task, getting Jeter on an RBI groundout and Hideki Matsui on a roller to shortstop.
"It was good," Ortiz said. "You have your fifth starter picking up your fourth starter -- that's a plus. He's pitched some really big games for us this year."
The Red Sox got some breathing room in the seventh. Coco Crisp stole second with two outs -- several Yankees appeared unhappy with the call by umpire Joe West -- and scored on Julio Lugo's single. Youkilis' RBI double chased Mussina, and Ortiz's single off Mike Myers made it 7-2.
Youkilis and Ortiz singled in the first before Ramirez drove a 2-0 pitch over the left-field fence for his seventh homer this season and No. 477 in his career.
It was Ramirez's 51st home run against the Yankees. Only four players have more: Jimmie Foxx (70), Ted Williams (62), Hank Greenberg (53) and Carl Yastrzemski (52).
Lowell led off the fourth with his ninth homer to make it 4-0.
Rodriguez just missed his fourth home run in four games when he hit a long drive to center with a runner on in the bottom half. Crisp made the catch on the warning track. Matsui later scored on a wild pitch.
- Youkilis extended his hitting streak to a career-best 15 games.
- Jeter pushed his hitting streak to 17 games with an eighth-inning single.
- With his 2,584th strikeout, Mussina passed Warren Spahn for sole possession of 25th place on the career list.