A's reliever Dan Otero threw a first-pitch changeup, and Pierzynski ripped it on a line to center field. Pierzynski thought he hit it out, but former Red Sox center fielder Coco Crisp made a catch at the wall.
"I hit that ball good," Pierzynski said. "The guy jumped up at the top of the wall and caught it. What can you do? Just frustrating, you know?"
The Red Sox used back-to-back home runs by David Ortiz and Mike Napoli in the bottom of the 10th inning Wednesday to beat the Twins 2-1 and sweep that three-game series.
Those timely blasts didn't signal an end to Boston's offensive slump. The Sox scored five runs in those three wins against Minnesota and have now scored a combined seven runs in their past four games. The Red Sox came into the game batting .244, tied for 11th in the American League.
Dustin Pedroia circles the bases after hitting a two-run homer off Scott Kazmir.
Pedroia had two of Boston's five hits against Oakland, a two-run homer off left-hander Scott Kazmir in the sixth and the double off Otero.
Kazmir struck out eight, walked none and gave up just two runs on four hits, improving to 9-2.
"We faced a tough pitcher," Pedroia said. "To be honest with you, I think our at-bats weren't that bad. We had some guys hit some balls at people. We got to find a way to have a big inning and get some momentum."
Red Sox manager John Farrell said he thought he was watching some more ninth-inning magic when the ball left Pierzynski's bat in the ninth.
"Off the bat I thought it was gone," Farrell said. "It could have been off the wall. Coco runs it down, and he's in that spot right where if it had a little more elevation it's a tie game."
Red Sox right-hander Jake Peavy had a decent start, allowing four runs, just three of them earned, over 6 1/3 innings while striking out four and walking three. He gave up a solo home run to A's left fielder Yoenis Cespedes in the third inning. Then in the fourth, former Red Sox shortstop Jed Lowrie hit a one-out double and scored on Stephen Vogt's bloop single with two outs.
The way the Red Sox are hitting, Peavy needed to be much better to avoid losing his fifth straight decision. He fell to 1-5 and hasn't won a game since April 25 at Toronto.
"We know the situation we've been in as a team," Peavy said. "Going out there you can't put your team too far behind. I certainly try not to do that. Kazmir was good."
Jake Peavy gave the Sox a chance Thursday night but fell to 1-5.
Peavy said he "physically didn't feel very good" in the early innings but found a better rhythm later in the game.
"I thought Jake battled, kept multi-runs off the board in any given inning," Farrell said. "He pitched around some trouble at times. Once again, we're in the ballgame going into the seventh inning. We didn't have too many opportunities. Kazmir has got a year started, halfway through. You see what he's put up not just against us but throughout the season so far. Once again, we're scrambling to create some opportunities."
And once again, Peavy came away with a loss.
"I don't feel sorry for myself one bit," Peavy said. "I got to get better and got to find a way to win."
Peavy blamed himself for a defensive mistake in the second inning that led to an unearned A's run. He gave up a leadoff single to Josh Donaldson, who lined a ball off the left-field fence, a foot from going out, then walked Lowrie.
Catcher Derek Norris then hit a hard ground ball back to Peavy. But instead of throwing to second to start a likely double play, he threw to third for the force. Third baseman Xander Bogaerts caught Peavy's throw on the run then made an off-balance throw to first for an error. Both runners advanced, and Lowrie scored on a ground out.
"If I go to second base on the ground ball, we probably don't give up a run on that unearned run," Peavy said.