President Obama mistakenly labeled an Ohio Democrat the next senator "from the great state of Illinois."

Obama made the error while acknowledging officials before his speech in Cleveland, Ohio, on Wednesday.

"The lieutenant governor and soon to be junior senator from the great state of Illinois," Obama said, before correcting himself. "I was thinking about my own … Lee Fisher is here."

Fisher faces Republican Rob Portman in November.

Coincidently, Democrat Alexi Giannoulias, who is running to be the next junior senator from Illinois, released a TV ad Wednesday featuring footage of an event he held with Obama.

The Portman campaign was quick to point to the president's error as a sign of "trouble" for Fisher. "How do you know your campaign's in trouble?," a Portman spokeswoman said in an e-mail. "When the leader of your party — whom you’ve personally asked for help — calls you the next junior senator from … Illinois?"

The National Republican Senatorial Campaign committee also noted the president's error in an e-mail to reporters.

In an interview with the Columbus Dispatch, Fisher said he has asked for Obama's help raising money. "We've talked about it, and all I would say is that we are in active discussions with the White House, and I've spoken personally to the president about it," the Democrat said. 

—This post was updated at 3:38 p.m.