NEW YORK (AP) -- The Baltimore Orioles did not expect Jorge Posada to swing away. So they certainly were surprised when he hit a game-winning homer.

Posada's three-run homer in the ninth inning with the infield charging in capped New York's second rally against Baltimore's beleaguered bullpen and gave the Yankees their fifth straight win, 12-10 on Friday night.

	Jorge Posada's three-run homer in the ninth was part of a four-hit night for the Yankees catcher.

"Everybody was expecting a bunt," Posada said. "With all of the infielders moving, I just wanted to hit the ball up the middle. But I got a good pitch and was able to do something with it."

Paul O'Neill led off the ninth with a homer off Mike Timlin, making it 10-9. Bernie Williams, who went 3-for-5 with four RBI, singled to knock out Timlin.

B.J. Ryan (1-2) came on and walked Tino Martinez, who is hitless in his last 11 at-bats.

The Orioles, anticipating a bunt, put on the rotation play and third baseman Cal Ripken was halfway home when Posada hit the first pitch into the left-field seats for his seventh homer.

"We had the bunt play on," said Ryan, who was trying for his first career save. "I didn't know what was going to happen. I was just trying to get it down and in and I left it out over the plate. I can't make that pitch at that time whether it's a bunt or not."

Yankees manager Joe Torre said he considered bunting the left-handed Martinez against the lefty Ryan, but wanted Posada -- who went 4-for-5 to raise his average to .337 -- to swing away.

"It's just a chance you take," Torre said. "I felt good about our situation and let it fly."

As Posada rounded the bases, he jumped on home plate and into his teammates' arms. The crowd started chanting, "Jorge! Jorge!" and Posada took a curtain call.

"It was a great feeling to do this here at Yankee Stadium," Posada said. "Everybody dreams about that."

Orioles relievers allowed seven runs in the final three innings to spoil the first start of the season for Scott Erickson, who allowed five runs in six innings in his return from elbow surgery. They blew two save opportunities and have blown seven of 11 chances this season.

Jeff Nelson (5-0) pitched 1 1/3 scoreless innings for the win as the Yankees bullpen improved to 9-0 despite allowing three runs.

There were runs scored in every inning and the teams combined for six homers and 30 hits. The Yankees, who won three nailbiters in Cleveland this week, have won five straight.

"That was lot more entertaining than we like to be," Torre said. "We're not a team that outslugs people. This was a gift for us."

Williams had tied the game at 8 in the seventh with a three-run homer off Buddy Groom, who cost Erickson the win.

B.J. Surhoff and Harold Baines hit two-run homers to knock Orlando Hernandez out in the fifth inning. Ripken added a solo homer -- the 407th of his career, tying Duke Snider for 28th place -- in the second.

Delino DeShields had four hits and four runs scored for Baltimore.

"You hate to score 10 runs, not make any errors and still not win the ballgame," manager Mike Hargrove said. "That's not supposed to happen."

The Orioles had taken a 10-8 lead by scoring twice in the eighth inning against Mike Stanton on an RBI double by DeShields and a sacrifice fly by Surhoff.

After the Orioles took the lead on the homer by Surhoff and Baines, the game was interrupted when eight protesters angered by the arrest of protesters on Vieques Island near Puerto Rico rushed the field.

With one out, the protesters ran on the field waving Puerto Rican flags. Security guards ran out and tackled them and escorted them from the field. One of the protesters handed something to Williams -- a Puerto Rican native -- but he wouldn't reveal what it was.

"I don't know what they were trying to do," Williams said. "I certainly understand their situation and feel for them."

The Yankees took a 3-0 lead in the first inning off Erickson on an RBI double by Williams, a run-scoring groundout by Tino Martinez and an RBI single by Jorge Posada.

An error by Wilson Delgado at second base helped Baltimore tie it in the third inning.

Hernandez allowed seven runs -- six earned and nine hits in four-plus innings.

Game notes
O'Neill robbed Belle of a homer in the second inning with a leaping grab in front of the right-field wall. ... Williams, normally a slow starter, has 31 RBI in 28 games. At that point last season, he had only 14. ... After starting the season 3-0 with a 1.74 ERA, Hernandez is 1-1 with a 9.18 ERA his last three starts. ... Baines moved past Andre Dawson and into 24th place with 1,592 RBIs. Ripken has 1,590, second among active players.