After Miami took a 3-2 lead in the 10th inning, Cishek tried to close out his sixth save. Instead, he was tagged with his second blown save in seven opportunities.
Cishek surrendered a leadoff, game-tying home run to John Mayberry Jr., who belted a 2-2 slider over the wall in center field. In the 11th, Mayberry struck again with a walk-off grand slam off lefty Edgar Olmos.
Cishek has been hurt a few times by the long ball this season. The home run was the third he's allowed in 24 innings. In 2012, he gave up three home runs in 63 2/3 innings.
"It's tough. Your team is relying on you to put that game away," Cishek said. "They fought so hard, and it's in your hands to get three outs right then and there to shut the door."
Prior to Tuesday's home run, Cishek had been getting back on track.
After posting a 5.25 ERA in April, the right-hander's ERA was 3.48 in May, with three of the four runs he allowed coming on May 16 in a 1 2/3-inning outing against the Reds.
"In his last couple of outings, he had been really good," manager Mike Redmond said. "He just threw what looked like a flat slider there, and [Mayberry] just crushed it. That's the way things have been going."
Joe Frisaro is a reporter for MLB.com. He writes a blog, called The Fish Pond. Follow him on Twitter