BOSTON -- The seventh inning left Doug Mientkiewicz bruised and dazed on the Fenway Park infield, clumps of dirt sticking to his hair and face. The rest of his Yankees teammates could sympathize.

The Red Sox erupted to regain the lead in a stunning five-run seventh inning that featured two errors by shortstop Derek Jeter and an apparent head injury suffered by Mientkiewicz, as Boston defeated New York, 11-6, on Saturday.

The contest featured continued struggles by starter Mike Mussina, who allowed five runs in five-plus innings and gave back a lead, and by reliever Scott Proctor, who was charged with five runs (two earned) and his third loss.

All this on a day when the Yankees also confirmed that seven-time Cy Young Award winner Roger Clemens is suffering from a fatigued right groin and won't be arriving to lend a hand as soon as expected.

Yet somehow manager Joe Torre felt inspired to offer a positive spin on the day's events, rejecting the idea that it had somehow spoiled his team. The ugliness of the seventh inning aside, Torre said his club had an inspired feeling about its play.

"The result deflates us, but we haven't had this feeling about going out and playing baseball for a while," Torre said. "Don't ask me what the reason is, that all of a sudden it's here. But they're competitive right now."

Regardless, it wasn't enough to lead the Yankees to a third straight victory. The tone may have been set in the fourth inning, when brief rains delayed the game for 29 minutes and appeared to affect both Mussina and his Boston counterpart, Curt Schilling.

"The rain delay at that point in the game, fourth inning, is really tough," Torre said. "If it happens in the first two innings, it's really not an issue. I think you saw what happened to Schill -- he just had trouble getting back."

Boston tacked on two runs in the waterlogged frame, as David Ortiz walked and moved to third on Manny Ramirez's double. After the delay, Mike Lowell came through with a run-scoring single, and a second run scored as Jason Varitek bounced into a double play on which Lowell flattened infielder Robinson Cano, sending the second baseman sprawling with a body check.

After the game, Cano cried foul on the hit, claiming Lowell had stopped in the baseline and dropped an elbow into Cano's arm. Torre called it a clean play from the bench, but Cano clearly did not agree.

"I've never had a problem with him before," Cano said. "I don't think it's a fair play. He threw his elbow at me."

Yankees Coverage
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Yanks gear up for lesser opponents
Chamberlain springs curve on Sox
Notes: Peace of mind for Posada

Red Sox Coverage
Schilling's gem ends with loss
Bauman: Game mirrors Classic duel
Sox don't take lead for granted
Notes: Matsuzaka pushed back
Season Series
Yankees win 10-8
• 9/16: Yankees 4, Red Sox 3
• 9/15: Red Sox 10,Yankees 1
• 9/14: Yankees 8, Red Sox 7
Previous season series
2006: Yankees 11, Red Sox 8
2005: Yankees 10, Red Sox 9
2004: Red Sox 11, Yankees 8

Not to absolve Mussina, but neither hurler came back particularly effective after the delay. After Schilling had surrendered a third-inning homer to Melky Cabrera, the Yankees rallied for four runs in the sixth to regain the lead and chase Schilling.

Hideki Matsui singled and Alex Rodriguez walked to begin the inning against Schilling, who worked to a 2-2 count before Posada went down and blasted his ninth roundtripper of the year over the right-field wall. Mientkiewicz added a run-scoring single off Javier Lopez later in the inning to extend New York's lead.

Boston's offense showed it could flex as well, and had little sympathy for the troubled and struggling Mussina, who has a 6.25 ERA and has been little help to a Yankees rotation in need of whatever it can get.

"I was just battling with everything I could think of from the beginning, because I didn't feel like I had really good stuff," Mussina said.

Staked to a two-run lead for the sixth, the Yankees stayed with Mussina, and it cost them, as the right-hander gave the lead back and did not retire a batter.

Lowell and Jason Varitek clubbed back-to-back home runs, with Lowell reaching the top of the Green Monster in left and Varitek unloading to straightaway center field. Mussina allowed five runs and nine hits in five-plus innings, walking four and striking out one in a no-decision.

"It's becoming too much, too often," Mussina said. "It's very frustrating and I'm really getting tired of it. I go out and one game is good and one game is bad. I've never pitched this way and I don't like pitching this way. I can't stand it."

The Yankees had one more gasp in the seventh, as Jeter gave New York a short-lived lead by reaching out to drive a full-count offering from Boston's Joel Pineiro over the left-field wall and into the Green Monster seats.

But it came unraveled in a bottom of the seventh that left one Yankee physically dazed and the rest spiritually so. Moving into a split to try and corral a throw from Jeter, Mientkiewicz was clipped in the back of the head by Lowell's lower half, dropping Mientkiewicz as a second run scored on the play.

After a delay for medical attention, Jeter committed another error on a Wily Mo Pena grounder to prolong the inning, and Coco Crisp added an RBI single against Proctor before Julio Lugo and Dustin Pedroia both brought in runs facing reliever Brian Bruney.

"You'd like to shut them down," Jeter said. "But their team is capable of scoring some runs quick."

"You give any club extra outs and it's dangerous," Torre said. "You give this club extra outs, and it's suicide."

The events left Torre to lean over to bench coach Don Mattingly and marvel that, once again, nine innings of baseball at Fenway Park had created far more to talk about than just a game.

"Stuff happens here, there's no question," Torre said. "I'm sure it goes on with other teams, too, but it always seems to happen when we're in town."