(CNN) - Republican Sen. John McCain - who has debated both President Barack Obama and GOP nominee Mitt Romney - weighed in Sunday on the upcoming showdown between the two candidates, saying both candidates will be "excellent in their own way" during this year's first presidential debate on Wednesday.
"I think both candidates are well prepared, and understandably, you'll see their surrogates lowering expectations," McCain said on CNN's "State of the Union." "That's part of the whole routine."
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In fact, the two campaigns have been boosting the other team in recent days. Romney's running mate, Rep. Paul Ryan, described Obama as a "very gifted speaker."
"The man's been on the national stage for many years, he's an experienced debater, he's done these kinds of debates before," Ryan said in an interview that aired Sunday on Fox News. "This is Mitt's first time on this kind of a stage."
Meanwhile, Obama's team points to the more than 20 debates in which Romney took part during the Republican presidential primary this cycle.
"He's prepared more than any candidate I think maybe in history, certainly in recent memory," Obama political adviser David Plouffe said Sunday on ABC's "This Week," adding he believes Romney will "probably have a good night on Wednesday night."
As the 2008 Republican presidential nominee, McCain battled Romney during the GOP primaries, then competed against Obama during the general election debates. The Arizona senator said Sunday that Romney may have a leg up on Obama due to his experience in the primary debates, but argued other factors are at play.
"I think you could argue that Mitt has had a lot more recent experience, obviously, but also, Candy, part of it depends on who is moderating," McCain told CNN chief political correspondent Candy Crowley, who will moderate the October 16 debate. "The tenor of the questions are dictated by that."
McCain added he expects Wednesday's debate to be one for the books.
"I think you're going to see more viewers at this first debate than you have in history," he said.
McCain, however, said he 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," McCain said.
Obama heads 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.
Meanwhile, the Romney campaign told CNN that Sen. Rob Portman of Ohio, who's playing the role of Obama in Romney's debate practice, will travel with the former Massachusetts governor on Monday to Colorado. Romney will hold a rally in Colorado that night before final debate preparations.
McCain on Sunday also weighed in on why Romney is trailing the president in polls measuring support in certain swing states, saying voters are starting to feel more confident about their economic prospects.
"I think he is behind because Americans probably feel better than they did before about jobs and the economy, even though it's terrible," he said. "I think Americans see a glimmer of hope."
A CNN/ORC International poll just after the Democratic National Convention earlier this month asked likely voters which candidate is more likely to win the debates. The poll results give Obama a 25-point (59%-34%) advantage over Romney.
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