Boston ? The “M-V-P” chants hadn’t been heard at Fenway Park in a while — at least not when David Ortiz was at the plate.

After a career year that carried the Red Sox into the playoffs and transformed him from a spare part to a star, Ortiz was hitless in his first 16 at-bats of Boston’s playoff series against Oakland.

All it took for the cheers to return was one more clutch hit.

The Red Sox designated hitter snapped out of his slump and saved the season with a two-run double off closer Keith Foulke in the eighth inning Sunday as Boston rallied to beat the Athletics, 5-4, and send the series to a decisive fifth game.

“David was holding his head down quite a bit, but we were telling him he has a great shot of being MVP,” said Boston outfielder Johnny Damon, who homered and threw out a runner at third. “Zero-for-16 doesn’t make or break a year, but that one hit you got certainly does.”

It was the eighth consecutive elimination game Oakland has lost — the longest slump of its sort in major-league history. Despite making the playoffs each of the last four seasons, the A’s have yet to advance past the first round.

“This is this year. We’re worried about this year,” Oakland second baseman Mark Ellis said. “We’re trying to make some new history and win that Game 5.”

To change their luck, the A’s will need to beat Boston ace Pedro Martinez after the teams fly cross-country for today’s fifth game. Barry Zito will pitch for Oakland on three days’ rest.

“I think we have the better team,” said Tim Hudson, who started Game 4 but left after just one inning because of a strained muscle in his side. “We have the best left-hander in the league going tomorrow.”

But Boston believes it has the best right-hander.

boston's david ortiz reacts after blasting a two-run double in the eighth inning. The Red Sox won, 5-4, Sunday in Boston.

“It’s all right,” Hudson said, “I’ll take Barry Zito over Pedro Martinez any day.”

The Red Sox were equally confident, remembering their rally in the 1999 playoffs when they came back from a 2-0 deficit to beat Cleveland in the first round. Martinez also pitched Game 5 that year, coming out of the bullpen to throw six hitless innings.

“We’ve got the best pitcher on the planet going,” said Red Sox starter John Burkett, who allowed four runs and nine hits in 51/3 innings.

And now they have their hitters going, too.

Despite starting the year as a fill-in first baseman and DH, Ortiz had 16 game-winning RBIs in the regular season — second-most in the AL. Twenty-four of his career-high 101 RBIs put the Red Sox ahead, and 42 came with two outs; he also set career highs with a .288 average and 31 homers.

But coming into the game, Ortiz and Manny Ramirez had combined for just one hit in 25 at-bats — a power outage in the middle of the lineup that was responsible for putting Boston at the brink of elimination.

Ramirez singled twice Sunday. With Boston trailing 4-3 and two outs in the eighth, he followed Nomar Garciaparra’s double with a ground single to left; Garciaparra went hard around third base, but coach Mike Cubbage held him up.

Ortiz worked the count full before lining a double to deep right, turning Jermaine Dye around as the ball went over his head. Garciaparra and Ramirez scored to give Boston the lead, and the “M-V-P!” chants began anew.

“I couldn’t think of a better time for that to happen, because the clock was running out there,” Red Sox manager Grady Little said. “That was a good time for them to bust loose.”

Scott Williamson pitched two perfect innings for the win, getting Erubiel Durazo to pop up to third base for the final out. For the third time in as many games at Fenway — the wild-card clincher, then Games 3 and 4 of the division series — the Red Sox poured out of the dugout to celebrate.

“This is the happiest I’ve ever been for a five-hour flight,” Boston first baseman Kevin Millar said.