Mariano Rivera (search) had it all in his hands: the save, the sweep, the pennant.

He just let it slip away.

Baseball's most reliable closer blew his second lead of the postseason Sunday night, and the Boston Red Sox (search) staved off elimination by rallying for an improbable 6-4, 12-inning victory over the New York Yankees in Game 4 of the AL championship series.

"Hey, it's one game. We've got another one to go tomorrow," Rivera said. "Actually, today."

The Yankees still need only one win in the next three days to advance to the World Series (search), but you have to wonder if they already wasted their best chance to close out the Red Sox.

Maybe a rare failure by Rivera in such a big situation is finally the turning point in this one-sided rivalry. Maybe it's the break Boston has been waiting 86 years for, since its last World Series title. Maybe if the Red Sox get rolling, New York will begin to panic.

Maybe, after laboring through 40 pitches and two tense innings, Rivera won't have much left on Monday, when the Yankees will face Pedro Martinez at Fenway Park.

"I will be there," Rivera said. "Been there before and this is no different."

Curt Schilling, injured ankle and all, is expected to pitch Game 6 for Boston at Yankee Stadium — if it gets that far.

"We know they're not going to give up," Derek Jeter said. "But we're exactly in the position we want to be in."

Regardless, Rivera no longer is automatic in October. He coughed up an eighth-inning lead in Game 2 of the division series against Minnesota, though his teammates bailed him out and won.

No such luck this time. He gave up a leadoff walk to Kevin Millar in the ninth and a tying RBI single to Bill Mueller, who also hit a game-winning homer off Rivera on July 24. It was one of two times Boston beat the All-Star closer this season.

"Any team in baseball would want Mo on the mound in the ninth inning," Jeter said. "I'm sure all those guys would tell you they don't like to face him."

One of the key plays came from pinch-runner Dave Roberts, who stole second after Millar's walk. Rivera thought Mueller would be bunting, but he smacked a single up the middle instead.

"I don't consider that frustrating," Rivera said. "I walked the first guy — you can't do it. To me, that was the key."

Rivera escaped a bases-loaded jam and kept it tied at 4 by getting David Ortiz to pop out, but he looked tired in the dugout as he watched the game go to extra innings. Ortiz won it for the Red Sox with a two-run homer off Paul Quantrill in the 12th, ending the longest game in ALCS history after 5 hours, 2 minutes.

"We scored a run off the best relief pitcher in the history of baseball with our backs against the wall," Doug Mientkiewicz said.

The series started with all eyes on Rivera, who returned home to Panama after two family members were electrocuted in his swimming pool last weekend. He attended the funeral Tuesday, then raced back to New York in time to save Game 1 after the Yankees blew most of an 8-0 lead.

Rivera spoke softly about crying on the lonely flight back and the range of emotions he was going through. He said he wished he could have stayed in Panama to comfort his family, but he had a job to do and his teammates were counting on him.

"Having a one-run lead in the ninth inning, it certainly is disappointing," manager Joe Torre said. "We're so used to Mo going out there and getting people out, which he did tonight. It's just that the walk and the stolen base was the difference in that ninth inning."

Torre always talks about how much he trusts Rivera, but perhaps he's asking too much of the 34-year-old reliever these days. Rivera got a pair of four-out saves in the first two games, and he was trying to get six outs in this one.

"I thought it was an opportunity, especially the way the eighth inning we were facing their three, four, five guys. That's like a save situation going through the heart of the lineup," Torre said. "He was the only one available. He had not pitched in three days before that."

Rivera came up short, only his fourth blown save in 36 postseason chances. And it certainly cost the Yankees this time.

"You put the walk away, and it would have been totally different. But it wasn't the way I planned it today," Rivera said.