ABC News' John Berman, Sunlen Miller and Matthew Jaffe Report: Barack Obama no longer shared the stage with John McCain, but the Illinois senator used a rally before thousands in Greensboro, N.C. to continue the argument from the first presidential debate. "We talked about the economy for forty minutes," Obama told the crowd. "And not once did Senator McCain talk about the struggles that middle class families are facing every day right here in North Carolina and around the country."It was a point the Obama campaign was clearly eager to make, as they released a new television commercial entitled "Zero." The ad uses debate footage while an announcer wryly states, "Number of minutes in debate: 90. Number of times John McCain mentioned the middle class: Zero."While the majority of Friday night's debate in Oxford, Miss. focused on foreign policy, Obama's 30- minute speech in Greensboro, delivered with the help of a teleprompter, stuck to issues surrounding the economy and the financial crisis facing the country. And as much as he could, Obama tried to lay the blame at the feet of John McCain. "Times are hard. I will not pretend that bringing about change will be easy," Obama said. "George Bush has dug us into a deep hole. John McCain was carrying the shovel."While hitting themes he addresses regularly on the trail, Obama also dropped in repeated references to Friday's debate. Of McCain, he said, "I don't know how he stood up there trying to defend what's been taking place or trying to distance himself from what's taking place because it was just a few months ago that he bragged he had voted with George W. Bush 90 percent of the time."It also seemed Obama tried to get in some licks he might have missed at the debate. "You see, I think Senator McCain just doesn't get it," he said, repeating a line he uses on the stump but neglected to mention on stage in Oxford. "[McCain] doesn't get this crisis on Wall Street, he doesn't get the fact that it hit Main Street a long time ago."Today McCain campaign spokesman Tucker Bounds responded to the comments Obama made in Greensboro."Barack Obama has a selective memory because John McCain repeatedly pointed to Senator Obama's vote in favor of higher taxes on families making just 42,000 a year, and his proposal for $860 billion in lavish new government spending which is a crushing burden on middle class families and the Main Street economy," the McCain campaign said in a statement. "If he was honest, Barack Obama knows he was unable to debate the merits of supporting higher taxes on the middle class, and bloated government spending during a looming economic crisis – it simply proved indefensible last night."Obama also had a rare guest on the stage with him today, his running mate Joe Biden. It was the first time Obama and Delaware senator campaigned together since August 31st in Battle Creek, Mich. Biden introduced his running mate saying, "Last night, America looked at a person, the person sitting here to my left, and they just didn't see a winner last night, they saw the next commander in chief."As Democrats have done since the Oxford duel ended, Biden said Obama had won a debate on foreign policy that was supposed to be McCain's strong-suit."The foreign policy, the national security policy - the focus of last night's debate - this was supposed to be John McCain's turf. And Barack Obama owned it last night," Biden said.For his part, Obama won some laughs at the expense of his partner. He told the crowd he liked Biden's common touch, explaining, "One of the reasons I am so proud to be with Joe Biden – it's not just his fancy foreign policy expertise, its not just because he's a sharp dresser." Biden grinned like a cat while Obama added, "I noticed a lot of women have been talking about Joe lately, I noticed that. See these girls right here."One slightly ironic moment came when Obama ribbed McCain, suggesting he is trying to co-opt the issue of change. "He's been grabbing our signs. Using our slogans. He even said the other day, the other day he said, I think, we need to turn the page." These are all lines or themes Obama uses regularly on the stump. Obama added, "Pretty soon I'm gonna have to start saying I'm a maverick! You gotta come with your own stuff!" Of course, Obama's running mate Biden knows all too well the perils of borrowing campaign themes. In 1988, he dropped out of the presidential race after reports surfaced that he used lines from a British politician, without attribution.The event today was also notable for its geography. North Carolina is a state that has been solidly in the Republican column in recent presidential elections. But polls show the race is close here, and Guilford County, home to Greensboro, is one of the few reliably Democratic counties in the state. John Kerry won the county by less than 2000 votes in 2004. Obama and Biden plan to stay together for events in Virginia later Saturday, and then at rally in Michigan on Sunday.