"We have a candidate who is going to do extraordinarily well on Wednesday night," Chris Christie said on "Face the Nation" on CBS. The Republican governor said Romney will have his first chance to directly contrast his vision for the country with that of Obama.
"This whole race is going to be turned upside down come Thursday morning," Christie said.
McCain -- who has debated both Obama and Romney -- also predicted Romney will fare well this week. He said the debate will likely have more viewers than any other presidential showdown in history and argued that both candidates will "do excellent in their own way."
"I think you could argue that Mitt has had a lot more recent experience, obviously," McCain said on CNN's "State of the Union."As the 2008 Republican presidential nominee, McCain battled Romney during the GOP primaries, then competed against Obama during the general election debates. While he foresees a record audience Wednesday night, McCain doesn't anticipate any major "breakthrough" moments from the debates, saying those have become far and few between in the last couple of decades.
"I can't remember the last time there was one of these comments that grabbed everybody's attention because, frankly, the candidates are too well prepared. They're well-scripted," the longtime senator said.
Obama, meanwhile, flew to Nevada on Sunday, where he'll hold a rally before digging in for a few days of preparation ahead of Wednesday's debate in Denver. Sen. John Kerry of Massachusetts, who's playing the role of Romney in the president's debate practice, will join Obama this week in Nevada.
The president's campaign spokeswoman, Jen Psaki, told reporters on Air Force One that Obama likely won't be flinging barbs during this week's presidential debate.
"If you're expecting that, that's probably not what he's going to deliver," Psaki said." He's speaking directly to the American people and what they want to hear is what his plan is for moving the country forward."
Psaki was referring to reports that Romney was "working on zingers" and memorizing short attack lines to fire off at the president on Wednesday, the first presidential debate this cycle.
Psaki added the president's focus will be more trained on the audience at home than his competitor on stage.
"This will be a very large audience. He wants to speak directly to the families, the people on their couches at home, having snacks, drinking a beer, drinking a soda, whatever it is, and tuning in for the first time. And that's who he's speaking directly to," she said.
Political experts agree much is at stake in the first debate. Obama leads most national polls and has a significant advantage in polls in several key battleground states where the race is expected to be decided.
A number of political analysts have said that Romney's best chance of getting some momentum for his campaign will come in the debates, which stretch over most of October and leave two weeks of campaigning before Election Day.
The first debate will set the stage for the final weeks of the race, said Republican strategist and CNN contributor Alex Castellanos.
"This is their first chance -- our first chance to see the two gladiators in the arena alone, so how they -- who is the Alpha dog in this debate? That's what we want to see. Because if you can't beat the other guy, how can you lead the country?" Castellanos said on "State of the Union."
Furthermore, Castellanos said Romney will face pressure to show a likability factor on the debate stage but said his best bet is to "show us what he would do as president the next four years," something Castellanos argues Obama has yet to clarify.
"Romney, his canvas has a little bit of blank space there. He could do that," he said. "But clearly, this debate is one of those rare political events where both candidates are the underdogs."
Meanwhile, on the expectations front, both campaigns continued Sunday to set the bar low, a game the teams have been playing for well over a week.