A popular player in Oakland, Cespedes played his first 365 games with the A's and hit 66 home runs, driving in 229 before he was traded to the Boston Red Sox at the Trade Deadline last July.
He was cheered every time his name was announced during the three-game series.
"I feel happy and honored that these fans still appreciate me," Cespedes said. "I still have a lot of affection for that team. But I play for this team now and I want to win."
He hit the homer against former teammate Dan Otero, though he said that was not an advantage.
"I know what he throws, but I never faced him," Cespedes said.
The Tigers started their rally with two outs. Ian Kinsler doubled to end an 0-for-22 streak and the A's elected to intentionally walk Miguel Cabrera, who had his 13-game hitting streak end.
"Most hitters are motivated when the guy ahead of him gets walked," Tigers manager Brad Ausmus said. "It seems like it always happens that when you trade a guy he comes back and hits a home run."
Cespedes said he wasn't looking to hit a home run, but that he was a little more determined when Cabrera was walked.
"I concentrated a little more," he said. "I was pretty confident I would do something."
Cespedes was moved up in the order to hit fourth, the second time he's been in the cleanup spot all year. He's hit fifth or sixth a combined 45 times.
"It worked today," Ausmus said. "Sometimes you get lucky."
Rick Eymer is a contributor to MLB.com This story was not subject to the approval of Major League Baseball or its clubs.