His second homer of the night and 31st of the season, a two-run blast to the first row of the right-field grandstands off Al Reyes, lifted the Red Sox to a 5-4 win over the Rays in the rubber game of the three-game series at Fenway Park on Wednesday.

"I thought it was too high," said Ortiz, who drove in all five of Boston's runs. "That was a good pitch by Reyes, but I put a good swing on it. It looked like a cutter in. It's a pitch you make when you don't want a guy to extend [his arms]."

Rays right fielder Delmon Young overran the ball, reaching the Pesky Pole before retracing his steps, but not in time as the ball fell in the first row.

"[The] wind was kind of crazy tonight, but it worked the right way," Ortiz said.

The win allowed the Red Sox to maintain their five-game lead over the Yankees, who beat the Blue Jays at Rogers Centre, and put Boston's magic number to clinch the American League East title at 12.

"It's not just the walk-off, it's the situation we're facing right now," Ortiz said. "[The Yankees] have been playing

really good, and you lose this game and then they win [Thursday], and it changes the whole thing. The way they've been playing, you want to be sure you win some games."

"That's the biggest thing, is keeping that five-game lead going into this next series and especially, the momentum," added winner Jonathan Papelbon (1-2), who pitched a perfect ninth. "With the last two, three weeks of the season left, this [win] is absolutely huge for our ballclub going into this stretch run."

It was the first time all season that Ortiz had the chance to make his traditional helmet toss rounding third base.

"It felt good," said the hero. "That means the game is over, and you have to make sure your teammates don't beat the crap out of you."

Not only was it the first walk-off homer of the season for Ortiz, Wednesday marked the first time the slugging designated hitter ended a game this season with a hit of any kind. It was also the first time Boston had a walk-off homer since current Rays first baseman Carlos Pena hit a solo homer to beat the White Sox, 3-2, on Sept. 4, 2006, at Fenway.

In the third inning, Ortiz launched a 97-mph fastball from Tampa Bay starter Edwin Jackson to the right-field bleachers for a three-run homer, his 30th of the season. The two long balls also gave him 104 RBIs, moving him two past the ill Mike Lowell for the team lead.

"It's that time of year and ... I think he's definitely one of the guys," Red Sox manager Terry Francona said. "He had good swings all night. He lined out a couple of times, he hit the three-run homer, that was, up to that point, our only offense. And he was seeing the ball real well."

It is the fifth straight season Ortiz has belted at least 30 homers and driven in 100 runs. Only three other Red Sox have as many as five 30-homer seasons, including Ted Williams (eight), Manny Ramirez (six) and Jimmie Foxx (five).