BALTIMORE — Eric Gagne sat slumped in front of his locker, still wearing his Boston Red Sox jersey.

Red Sox starter Daisuke Matsuzaka delivers a pitch against the Orioles during last night’s game at Baltimore.

AP / Nick Wass

His back was to the center of the room, where the media was gathering to approach him for a postgame chat.

Gagne was trying to process his thoughts, going over and over in his mind the four runs he gave up as part of a two-man bullpen meltdown that turned the rallying Red Sox’ four-run lead into a disheartening 6-5 loss to the Baltimore Orioles at Camden Yards last night.

Hideki Okajima was the losing pitcher. He blew the save by allowing an RBI single through the shortstop hole by Melvin Mora in the eighth and then surrendered the losing run in the ninth on a leadoff ground-rule double to center by Brian Roberts, a sacrifice bunt by Corey Patterson and a sacrifice fly to center by Nick Markakis.

All of which negated a spirited five-run surge in the eighth against superb Baltimore left-hander Erick Bedard and three relievers that turned a 1-0 deficit into a 5-1 lead and the prospect of a well-deserved victory for Daisuke Matsuzaka, who stifled Baltimore over the first seven innings in an excellent pitcher’s duel that lived up to its pregame billing.

Along the way there was a clutch two-out tying single by Wily Mo Pena, a surprise go-ahead bunt single by Julio Lugo, a two-run single by David Ortiz and an RBI hit by Manny Ramirez in the eighth, delighting the sizable contingent of Red Sox fans in the sellout crowd of 48,993.

It was a game in which the Sox showed little pulse offensively for seven innings, vaulted into a seemingly commanding lead and ultimately trudged off the field trying to make sense of it all as their American League East lead once again slipped to five games over the New York Yankees.

“It was a roller-coaster,” sighed Boston manager Terry Francona. “We’re scratching to get one run there (in the eighth) and we have a phenomenal inning. And then they do the same to us.”

Baltimore manager Dave Trembley, not surprisingly, was sitting at the opposite end of the emotional spectrum.

“Just goes to show you, you don’t give in, you don’t give up,” Trembley said. “We’ll bend but we won’t break. Tonight was a tremendous game for us. That (type of comeback) doesn’t happen very often against that team and against the back end of that bullpen.”

And it’s something that the Red Sox and their fans didn’t expect to happen when they dealt for Gagne at the trading deadline July 31.

The former All-Star closer, obtained from Texas for three players, was supposed to give Boston an extra shut-down arm out of the bullpen, shortening games in essence to six innings after which, if the Sox had a lead, the relief trio of Okajima, Gagne and Jonathan Papelbon would finish the job.

Okajima and Papelbon have been brilliant for the most part all season for the Sox. Gagne has not.

Last night marked Gagne’s fourth appearance for Boston. He has given up a whopping nine hits and has been charged with six earned runs in only 3 1/3 innings. That works out to an earned-run average of 16.22.

The outing against the Orioles was the worst. Corey Patterson greeted him with a double off the right-field wall. Markakis dropped a broken-bat RBI single to right. Miguel Tejada walked. Gagne bobbled Kevin Millar’s dribbler, and only Millar’s lack of speed allowed Gagne to throw him out. After Aubrey Huff delivered a hit that eluded a hard-charging J.D. Drew in right, turning a two-run single into a two-run double and putting the tying run in scoring position, Gagne was gone.

That is what was running through Gagne’s mind after the game. It all happened so fast. And when he finally turned and faced the media, Gagne, to his credit, had no excuses. It doesn’t matter that he’s pitching the eighth and not the ninth, he insisted.

“That’s bullcrap,” is the exact quote from Gagne on that score.

“That (adjusting to pitching the eighth instead of the ninth) is not that hard. That’s just an excuse. You gotta get three outs no matter what inning you’re pitching. I haven’t done the job the last four times out. No excuses. The adrenalin has been there. I’m just not making my pitches when I have to. I’m not locating my fastball. I’m not locating my changeup. I’m not locating my curveball.

“I’m not doing my job right now. I’m making it hard on everyone else,” Gagne said. “I’m not doing what I’m supposed to do.”

Neither did Okajima last night, but he, at least, has much success in a Red Sox uniform this season.

“It’s happened in Japan many times before,” said Okajima of his inability to shut down the opposition last night. “By (today) I’ll have forgotten about it.”

Nevertheless, it was a hard loss to just forget about for the Red Sox, who fell to 3-4 on the road trip with two games remaining in Baltimore.

skrasner@projo.com