The Indians have now lost 16 of their past 20 games, and they have had a lead in eight of those losses. They dropped to a season-worst 11 games under .500.
After the high point of the game, Duncan's grand slam, very little went right for the Indians. Starter Zach McAllister let the A's immediately get back the momentum with three runs in the bottom of the inning, and the A's eventually scored the go-ahead runs in the eighth with the help of a leadoff walk, the type of thing that keeps managers up at night.
"You have to let them hit their way on," manager Manny Acta said. "We haven't done that. We have allowed more runs than anybody and there is a correlation that we have walked more people than anybody. The walks continue to hurt us."
Joe Smith, who had been one of the Indians' best relievers lately, issued the leadoff walk to Chris Carter in the eighth. He then gave up a single to Brandon Moss.
"I got ahead of everybody like I wanted to, I just couldn't put them away," Smith said. "I had both of them 0-2 and they ended up getting on base. In a tie ballgame, that can't happen. You have to find a way to put guys away."
Vinnie Pestano was then summoned to face pinch-hitter Josh Reddick, who had been out of the starting lineup because of a sore tooth. He dumped a bloop single into left, loading the bases.
Josh Donaldson then lined a single, his fourth hit of the night, to drive in the go-ahead run. An out later, Cliff Pennington's sacrifice fly drove in an insurance run.
The Indians went down in the ninth against A's closer Grant Balfour, ending a night that began with such promise.
The Indians jumped to a 4-0 lead on Duncan's grand slam. The stage was set for Duncan by a walk and two singles. He then drilled a 3-2 pitch from Tommy Milone over the left-field wall. Duncan had just three hits in his previous 29 at-bats.
"It was just over the plate," Milone said. "I felt like I got it down enough, but he's a good hitter. He's got a lot of power."
McAllister then took the mound with a comfortable lead, but he couldn't hold it. He gave up three runs in the bottom of the inning and one in the fifth, as the A's tied the game, 4-4.
Acta was critical of a few specific parts of McAllister's game. He threw a changeup to Pennington, the No. 9 hitter, even though he'd just dominated him with a fastball, and Pennington hit it into right for a two-out RBI single. He also failed to keep an eye on Yoenis Cespedes at second base in the fifth inning, allowing him to steal third. Cespedes then scored the tying run on a sacrifice fly.
"I like the way this kid has thrown the ball but I can't expect him to be polished and pitch like a 10-year veteran," Acta said.
McAllister made it through the sixth inning without giving up a run, allowing him to continue his streak. He has not allowed more than four earned runs in any of his 14 starts this season.
Still, he was disappointed with his performance after his team gave him a 4-0 lead.
"Every pitcher wants to put a zero and get the guys back in and get some more runs and keep the momentum," he said. "It's frustrating when you are not able to do that."