The ad, "Convention Night," features McCain, poised to accept his party's nomination next week, congratulating Obama, who is the first major-party black presidential candidate, the Republican's campaign in Arlington, Va., said in a news release.

Obama's acceptance speech in Denver Thursday was to be delivered 45 years to the day that civil rights leader Martin Luther King Jr. delivered the seminal "I Have a Dream" speech.

"Too often the achievements of our opponents go unnoticed. So I wanted to stop and say, congratulations," McCain said in the ad. "How perfect that your nomination would come on this historic day. Tomorrow, we'll be back at it. But tonight senator, job well done."