The Red Sox’ Wily Mo Pena claps his hands as he rounds the bases on his grand slam.

AP / Nick Wass

BALTIMORE — The sound was different this time. Much different.

All too often when Wily Mo Pena has swung the bat, especially lately, it has resulted in the sounds of silence, an embarrassing and frustrating string of strikeouts, generally the result of a feeble wave at a breaking ball.

This was different. This time when Pena swung, he actually made contact.

And the sound of the ball hitting his bat on this pivotal eighth-inning pitch from Baltimore’s flamethrowing closer, Chris Ray, produced thunder, not to mention four runs for the Boston Red Sox.

By the time the ball came to rest beyond the fence in right-center, Pena was celebrating his third career grand slam, which vaulted the Red Sox to a 5-2 victory over the Orioles last night at Camden Yards.

The homer rewarded a strong effort by right-hander Josh Beckett (5-0), who, with one inning of help from Jonathan Papelbon (seventh save), became the third pitcher in Red Sox history to win five games in April, joining Babe Ruth (1917) and Pedro Martinez.

To say that this was a bolt out of the blue was an understatement. Pena, a powerfully built mountain of a man, has seduced the Red Sox with the prodigious blasts he can deliver — when he gets the bat on the ball.

Unfortunately, that’s the part of the hitting equation that has had Pena baffled in his career, first with Cincinnati and then with Boston.

In his 25 previous at-bats, Pena had whiffed an alarming 14 times, including one last night. In five games as injured Coco Crisp’s replacement in center field, Pena was punched out 10 times in 16 at-bats.

Little wonder that the Orioles intentionally walked Jason Varitek, filling the bases for Pena with one out in the eighth and Baltimore clinging to a 2-1 lead.

Pena tried not to think of his past failures. He tried to think of his previous at-bat, when he crushed a double to left-center. He also had lined out hard to first in his initial at-bat. He had a plan against Ray, he said.

“I didn’t want anything low and hit the ball on the ground (and into an inning-ending double play),” he said. “I was looking for something up to hit the ball in the air.”

The count went to 2 and 1. The next pitch was up and Pena crushed it, sending it through the heavy, drizzly air for the grand slam.

“It was a slider,” said Pena.

No, it wasn’t, said Ray. It was a fastball. Pitch recognition may have something to do with Pena’s troubles. But regardless of what it was, Pena mashed it, and suddenly the Sox were on top and all those whiffs didn’t seem to matter in the moment.

“I was clapping my hands. I knew it was gone,” said Pena. “I was getting frustrated. I knew I had all those strikeouts and (teammates) were telling me I have to be more patient. They’ve been trying to get me out with slider away, away, away. They told me to wait for my pitch. Now I can be more relaxed at the plate.”

No one was happier to see Pena contribute the way he did than David Ortiz, his good friend and fellow countryman.

“We work a lot together every day,” said Ortiz. “He has the right attitude. He comes to the park every day, prepared to work. When you’re a power hitter, you strike out a lot. And when you don’t play much, that makes it worse (to find timing and rhythm). But he works. And the next thing you know, boom.”

Manager Terry Francona actually had a decision to make while Ray was walking Varitek and filling the bases. Pena isn’t exactly a lock to hit right-handers these days, and he could have opted to bring in Eric Hinske, a left-handed hitter, to face Ray.

But that, he said, would have necessitated moving J.D. Drew from right field to center and putting Hinske in right because Crisp was unable to play. And he said he didn’t want to put Drew in center.

So, up stepped Pena. And just like that, it was 5-2, Boston.

“Wily Mo actually seemed frustrated (before the at-bat),” said Francona. “But he’s such a strong kid. When he gets the head (of the bat) to the ball, that’s what he can do. I thought he took better swings from the get-go tonight. That’s the one thing Wily Mo can do — hit a homer.”

Beckett appreciated the late run support, which made him a winner. He had had to work out of a couple of jams in limiting the Orioles to a run in the first and one more in the third, but he didn’t walk a batter in his solid eight-inning, 100-pitch effort.

“I felt fine. The weather was semi-cold, and it keeps you fresh,” said Beckett. “It’s nice (putting his name in the record books alongside Ruth and Martinez), but there’s still a long way to go. I don’t want to get too far ahead of myself.”

Beckett’s just fine where he is, though, and who would have thought it after seeing him swing lately, but he owes Pena for his one productive swing that made all the difference last night.

skrasner@projo.com