CHICAGO – President Obama was up early and visiting a campaign field office here in his hometown Tuesday.

The president made the unannounced stop to thank campaign workers and make a few last-minute calls to swing state voters. And he took a moment to pay tribute to a hard-fought campaign.

“I also want to say to Governor Romney, congratulations on a spirited campaign,” the president said. “I know that his supporters are just as engaged and just as enthusiastic and working just as hard today.”

But Obama sounded a confident note.

“We feel confident we’ve got the votes to win that it’s going to depend ultimately on whether those votes turn out,” he said. “And so I would encourage everybody on all sides just to make sure that you exercise this precious right that you have that people fought so hard for us to have.”

Taking a seat at the phone bank, the president made three calls, including to one woman in Wisconsin who didn’t seem to recognize his name.

"This is Barack Obama. You know, the president?" he was heard saying. “She was very nice to me even though she initially didn't know who I was," Obama said when the call ended.

He also took a sip from a cup of coffee that was not his tea. “I hope you don’t have a cold,” he joked to a staffer.

“No matter what happens, I just want to say how much I appreciate everybody who has supported me, everybody who has worked so hard on my behalf,” he concluded. “And again, I want to congratulate Gov. Romney and his team for a hard-fought race as well.”