Sox reliever Eric Gagne tries to gather himself after giving up a game-tying, two-run homer in the eighth inning.

AP / Nick Wass Nick Wass

BALTIMORE — It wasn’t supposed to be this way, of course.

When the Red Sox obtained Eric Gagne in a trading-deadline move on July 31, the plan was to make every game a six-inning contest.

Have Boston’s excellent starters go six innings, have the offense get a lead and then turn it over to Hideki Okajima for an inning, Gagne for an inning and Jonathan Papelbon to close it out over the final inning. Game over.

Well, this plan hasn’t quite worked as it was drawn up. It has been game over — but it’s the other team that’s winning at the expense of the Red Sox bullpen as Boston’s once seemingly insurmountable lead over the New York Yankees in the American League East has shrunk to a scary four games.

That, at least, is what happened again yesterday when Boston relievers torched a win for Curt Schilling in falling to the Baltimore Orioles, 6-3, on a three-run homer by none other than ex-Cowboy-Up Soxer Kevin Millar with one out in the 10th inning.

Millar’s blast came off Kyle Snyder, but the culprits yesterday were Okajima and, more chiefly, Gagne, who was tagged for a tying two-run homer by Miguel Tejada with one out in the eighth on the seventh straight fastball he threw to the Baltimore shortstop in the at-bat.

It was the second time in three games here that Okajima (who issued a leadoff walk in the eighth) and Gagne conspired to blow a lead. The duo, again chiefly Gagne, wasted a four-run advantage in the eighth in a game the Orioles won, 6-5, on Friday night.

And in both losses, the Red Sox’ best reliever — Papelbon — didn’t get into the game. In each case, Boston manager Terry Francona elected not to use Papelbon in a tie game on the road, hoping to be able to bring him in with the Sox ahead and a save on the line.

That scenario failed to materialize in both games, so Okajima surrendered the game-losing run Friday night and Snyder, who is on the bottom rung on the Sox’ relief-corps ladder, was victimized on a bunch of hanging breaking balls.

“It’s a situation where, obviously, you want to be in there. There’s no doubt about that,” said Papelbon, who notched a three-pitch save in Saturday’s game as the Sox wound up 4-5 on the three-city road trip.

“But you have to trust the program and what we’re trying to do as a team and what Tito wants to do,” he said. “It’s not an easy thing to sit, but we’re a unit in the bullpen. We thrive off each other. We root for each other. The team asks a lot of us and we ask a lot of ourselves. [What happened in Baltimore] is unexpected. But it’s baseball. You have to deal with the bad and the ugly. If it doesn’t kill you, it makes you better. That’s my philosophy.”

Gagne, meanwhile, doesn’t have to be reminded that his performances — he has allowed seven earned runs in four innings spread over his five Boston appearances for a 15.75 earned-run average and one blown save — have been killing the Red Sox.

“This is getting ridiculous. We should have won three out of three here and I blew two of them. They brought me here to do the job, and I’m not doing it. These guys played eight great innings and I go out and blow it. It’s a shame. I’m letting everyone down,” snapped the former All-Star closer, clearly upset with himself and again gamely facing the media, as he did Friday night, unwilling to offer up any excuses.

Gagne inherited a runner at first and one out when he entered the game. Boston had a 3-1 lead. Okajima had issued a leadoff walk and Nick Markakis had beaten out the back end of a double-play attempt, bringing Tejada to the plate, representing the tying run. And seven pitches later, Tejada was the tying run.

Gagne fell behind, 2-and-0, and just kept pumping in fastballs. The last three came in at 94, 95 and 96 mph, the last of which ended up in the seats in left-center, tying the game at 3-3.

“He fell behind in the count,” said Francona, trying to explain away the fact that Gagne didn’t go to any of his other pitches. “He’s a very dangerous hitter and he caught up with one.”

Gagne, who made some mechanical adjustments after an hour of studying video on Saturday, wasn’t impressed by the speed of the pitch.

“I don’t care if the (radar) gun says it was 120 mph. I’m not making my pitches. I’m messing it up for everybody,” said Gagne, who threw only curveballs and changeups in getting the next two hitters after Tejada’s blast.

Hanging curveballs proved to be Snyder’s undoing, too. Speedy Corey Patterson almost had to jump out of his shoes for a high hanger in lining a leadoff single to center in the 10th. Snyder went to the slide step to keep the speedy Patterson (32 stolen bases) close, and left a fastball up for Markakis, who drilled it to center, sending Patterson to third.

Snyder retired Tejada on a foulout to first but, after Markakis swiped second, the right-hander, who had Millar flailing at a curveball on the previous pitch for a strike, left another up and Millar lofted it for the game-winning homer.

“I put my myself in a situation where I had to get a strikeout there and had to go to a strikeout pitch for me, but I hung it,” said Snyder softly of the 2-and-2 pitch. “I tried to be careful, but I ended up hanging it.”

And thus it was that Boston’s long road trip came to a somber end, but, Sox fans, don’t panic, says reliever Manny Delcarmen, who gave up a hit but fanned three in the ninth inning.

“Just relax,” said Delcarmen, a Boston native. “We’ll be fine.”

skrasner@projo.com