BOSTON -- With a postseason berth at stake, Red Sox manager Terry Francona isn’t about to take any chances.

For only the second time this season, Red Sox closer Jonathan Papelbon was called upon to register a possible five-out save when reliever Daniel Bard, who had pitched a perfect seventh inning, was removed with one out in the top of the eighth after allowing a pair of singles.

Papelbon struck out the first batter he faced before the Orioles’ Nolan Reimold singled to load the bases. Robert Andino then provided a three-run double as the Orioles posted a come-from-behind victory and beat the Red Sox 7-5 on Tuesday night at Fenway Park.

“Unacceptable,” Papelbon said. “The way I’ve been throwing the ball, I’ve got to go out there and execute. I didn’t do that, and by me not going out there and executing 0-2 pitches, I let my team down. I’ll shoulder that and take full responsibility, and I’ll be ready to go tomorrow. It’s plain and simple.”

Francona explained his decision to bring Papelbon in early.

“We went to him early, and we told these guys we probably would,” Francona said. “I think we got far enough where we wanted to have Pap pitch to the lefty [Chris Davis] and we wanted to piece it together. It didn’t work.”

Papelbon said it doesn’t matter when he’s handed the ball during the course of the game; he needs to deliver.

“I welcome that,” he said. “This is the time of year where Tito, the coaching staff and everybody in this clubhouse is going to need to lean on guys, and I’m one of those guys. I didn’t come through tonight. This one is on me. I’ve got to learn from it, put it behind me, forget about it and come back tomorrow ready.”

Catcher Jarrod Saltalamacchia said Papelbon had his usual life on his fastball, and when he got ahead of Reimold 0-and-2, Boston’s closer tried to go fastball but couldn’t execute the pitch where he wanted.

Papelbon has been automatic this season. He entered the game with 30 saves and a 4-0 record, having converted 30 of 31 chances this season. So one blown save, even at this time of the season, isn't going to shake his teammates' confidence in him.

“Anytime Pap comes in the game, I don’t expect anything less,” Saltalamacchia said. “There’s not one guy who is more prepared than him. He’s a guy who wants the ball and is a competitor. Everybody, including myself, felt good about him being in there.”

Since the Tampa Bay Rays lost to the New York Yankees, Boston’s lead in the American League wild-card race remains at two games.

The Red Sox’s struggles continue this month, with their record in September now 5-15 with only seven games remaining in the regular season.

Before the eighth-inning implosion, the Red Sox held a 5-4 lead thanks in part to Adrian Gonzalez, who went 3-for-4 with three RBIs, including a two-run homer.

Red Sox starter Erik Bedard lasted only 2 2/3 innings and allowed four runs (one earned) on five hits. He walked two and struck out none.

The left-hander wasn’t helped when right fielder Josh Reddick committed a two-out error in the top of the third, which ended with Baltimore holding a 4-1 advantage. That miscue proved costly as Bedard threw 51 pitches in the inning.

“I just misread it,” Reddick said. “I came in, and he hit it harder than I thought he did. I jumped a little too late, and it caught the end of my glove. It was a bad read.

“It’s the worst feeling ever, knowing that you made your starting pitcher work a lot harder than he should have, and I should have caught that ball to end the inning, especially losing the lead like we did. There’s no worse feeling. It’s somewhere you don’t want to be.”

Bedard has been hampered by knee and lat injuries and hadn’t pitched since Sept. 3, but he insisted he’s healthy. With one word he described that four-run third. “Long,” he said.

“I just tried to battle and limit the damage,” Bedard said. “It happens. People make errors. It’s part of the game, and you try to limit the damage.”

He’s scheduled to start again either Sunday against the Yankees or Monday at Baltimore.

Boston needs Wednesday’s starter, Josh Beckett (13-5, 2.50 ERA), to stop the bleeding once again. The Orioles will have righty Tommy Hunter (4-4, 4.81 ERA) on the mound.

“There’s no reason for us to sit here and say the walls are crumbling down and it’s time to start panicking,” Papelbon said. “That’s not going to happen in this clubhouse. Every single person in this clubhouse has been through adversity. Adversity, in times like this, is what will make us better. Period. Point blank.”