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Cliff Pennington's swing had been off and he'd been limited for two games because of an infected sweat gland under his arm.

Entering with a .160 average and batting out of the No. 9 hole, Pennington faced a difficult situation in the ninth inning. The Oakland Athletics had scored but still trailed the Chicago White Sox by two. And now the bases were loaded with two outs.

Facing struggling closer Matt Thornton, Pennington delivered. He dropped a two-run single into center and the A's added three more in the 10th for a 7-4 victory.

"Matt Thornton on the mound throwing 97 miles per hour, I just tried to get a fastball I could hit and it fell in," Pennington said.

"That's what we have to do offensively — scratch and claw."

With the White Sox leading 4-1 in the ninth, Chris Sale gave up a leadoff double to Conor Jackson, an RBI single to Josh Willingham and a single to Hideki Matsui. Jesse Crain came on and walked pinch-hitter Daric Barton to load the bases before fanning Kurt Suzuki.

Thornton then struck out pinch-hitter Ryan Sweeney for the second out but couldn't get the ball past Pennington.

"I guess it's made news that those guys have been struggling a little bit, but you're bringing in Sale, Thornton and Crain out of the bullpen, those guys are all nasty and they've been nasty for a while," Pennington said. "They're going to be a really good bullpen, we're just trying to scratch a few runs across any way we can."

Coco Crisp entered in the ninth as a pinch runner and was in a 3-for-22 slump before singling off Thornton (0-2) to give the A's the lead in the 10th. The hit came right after Thornton — who is 0 for 4 on save opportunities this season — walked Jackson and Willingham.

Barton followed with a two-run single and Thornton was booed as he walked off the mound after being replaced by Tony Pena.

The White Sox now have lost late-inning leads three times in less than a week, twice to the A's, who also rallied to win Monday night's series opener.

"Oh man," Thornton said. "There's nothing to even describe it right now. Frustration is pretty high. ... Confidence isn't the problem. It's my frustration right now. It's the most frustrated I've been in a long time. I can't remember a run of games like this where I haven't gotten the job done that many times in a row."

Grant Balfour (1-1) pitched the ninth for the win and Brian Fuentes worked the 10th for his fifth save in five chances.

Oakland finished its road trip to Toronto, Minnesota and Chicago at 5-4.

"I just loved the attitude. The guys kept fighting right to the end," manager Bob Geren said. "We were down and it was going to take putting some hits together, drawing some walks, and we did it.

"I know their bullpen is struggling a little bit, it gives you a little bit of feeling of hope. They just battled. ... Think about the road trip, how many close games we've had, this one to finish it off, it's a really good feeling. It's going to be a nice flight home."

Oakland's rally denied John Danks a victory after he gave up a run and five hits in eight solid innings.

The White Sox broke a 1-all tie in the sixth against Oakland starter Brett Anderson when Carlos Quentin was hit by a pitch, Alex Rios doubled and a sliding Quentin scored on Ramon Castro's grounder to third that drew a high throw to the plate from Kevin Kouzmanoff.

Brent Morel dropped down a bunt to score Rios from third for a 3-1 lead. Juan Pierre's third single of the game chased Anderson (0-2), who was hurt by his own error in the fifth. Anderson gave up nine hits and three runs — two earned — in 5 2-3 innings.

"I was (in the clubhouse), sitting here and Pennington flared one in," Anderson said. "Especially as the starting pitcher on the hook for the loss, it's not only a comeback for the team, but a no-decision for you. It's good for everybody."

Matsui's second homer of the season put Oakland up 1-0 in the fourth. Chicago tied it in the fifth when Pierre reached as Anderson fumbled his comebacker for an error and Gordon Beckham doubled.

NOTES: Oakland's Andy LaRoche made his sixth start of the season at a fourth different position, this time getting the nod at first base.