OAKLAND, Calif. — Despite a third straight loss filled with missed opportunities, Boston Red Sox Manager John Farrell remains convinced his ballclub is on the verge of breaking out of its scoring slump.

It better happen fast.

The defending World Series champs are hanging on by a thread in the AL East following three straight losses, and not even a heads-up baserunning play by Dustin Pedroia was enough to snap Boston out of its funk.

Pedroia scored from third on a wild pitch in the eighth inning, but Oakland’s Coco Crisp singled in Alberto Callaspo with one out in the 10th to lift the Athletics to a 2-1 win over the Red Sox on Saturday.

“We are very close to becoming a team that will go on a run for an extended period,” Farrell said. “We’re close in a number of ways. That’s going to give us an opportunity to win every night.”

Boston had plenty of opportunities against the A’s, but like much of this series, failed to take advantage.

The Red Sox missed a chance to take the lead in the top of the 10th when Oakland reliever Dan Otero struck out David Ortiz with two on and two out. The Red Sox also stranded a runner at second in the third and another at third in the sixth.

It’s the seventh time in eight games Boston has been held to two runs or fewer.

“That’s whats so frustrating, we’re in these ball games,” Pedroia said. “It’s a break here or there. It’s one good swing from winning the game, and we haven’t done that.”

Pedroia provided one of the few highlights when he scored Boston’s only run.

Boston put runners on the corners with two outs when Oakland reliever Luke Gregerson appeared to strike out Mike Napoli. Napoli argued that he fouled the ball off the dirt, and home plate umpire Quinn Wolcott agreed although television replays appeared to indicate otherwise.

Under the current replay system, balls and strikes are not reviewable.

Gregerson, who had celebrated the apparent strikeout, bounced his next pitch in front of home plate. The ball ricocheted off the chest protector of catcher Stephen Vogt and rolled toward the mound as Pedroia scored from third.

“To be honest I really wasn’t paying attention to where (Pedroia) was,” A’s catcher Stephen Vogt said. “It was a great play by him. He must have been taking a couple of hard steps right away. It kicked away from me just enough to where he could sneak behind me.”

After Napoli flew out to end the inning, Oakland Manager Bob Melvin raced out from the dugout to confront Wolcott and was ejected.

The A’s overcame the play and won it in the 10th to improve to 4-2 against the Red Sox this season.

Callaspo drew a leadoff walk against reliever Edward Mujica (2-3) and was sacrificed to second. Red Sox closer Koji Uehara replaced Mujica, and Crisp lined Uehara’s first pitch into right field. Boston right fielder Brock Holt made a strong throw but Callaspo slid home with the winning run.