A leading Republican this weekend conceded that GOP presidential hopeful Mitt Romney has hit a rough patch, but said the coming debates with President Obama will be a game-changer. 

New Jersey Gov. Chris Christie (R) canvassed the Sunday news shows this week to trumpet Romney's debating skills and launch predictions that Wednesday's high-profile showdown in Denver will prove the turning point that propels the GOP ticket to victory. 

"I'm not gonna … come on this morning and sugar-coat the last couple of weeks – they've been tough," Christie said on CBS's "Face the Nation" program. "But here's the great news for Republicans: We have a candidate who is going to do extraordinarily well on Wednesday night – the first time he has the opportunity to sit on the same stage with the president of the United States, and the first time a majority of people who are gonna vote in this race will have the opportunity to make that direct comparison.

"He's gonna come in Wednesday night, he's gonna lay out his vision for America and he's gonna contrast what his view is to what the president's record is," Christie added. "And this whole race is gonna be turned upside down come Thursday morning."  

Appearing on Fox News Sunday, GOP vice-presidential nominee Paul RyanPaul Davis RyanDOJ delivers Russia probe documents to Congress Laura Ingraham: George Will is ‘sad and petty’ for urging votes against GOP Seth Rogen: I told Paul Ryan I hate his policies in front of his kids MORE delivered a similar message, saying the Wednesday debate will answer any lingering questions about "who is Mitt Romney, what kind of president will he be and what choice do I have." 

"Then the country understands the choice they have to make," Ryan said.

The predictions – particularly Christie's – are much stronger than those coming from the Romney camp, which has taken steps to lower expectations ahead of the debates.

"The president is obviously a very eloquent, gifted speaker," Romney told Fox News last week. "He’ll do just fine.” 

Still, with Romney dropping in the polls in recent weeks, many political experts see the debates as his last chance to reverse the trend and get on course to win the White House.

Former House Speaker Newt Gingrich (R-Ga.) said Sunday that the burden is on Romney, as the challenger, to make a clear case why he deserves Obama's job.

"He doesn't have to hit a home run, but Romney has to be, at the end of the debate Wednesday night, a clear alternative who's considered as a potential president by a majority of the American people in order for his campaign to have a chance to win," Gingrich told "Face the Nation."

"No challenger is going to become president if they can't stand up to the incumbent." 

The candidates seem to recognize the importance of the debates, as both have scheduled several days of intense preparation this week – Obama in Nevada and Romney in Denver.

Wednesday's debate is the first of three showdowns between Obama and Romney scheduled before the Nov. 6 elections. 

Sen. John McCainJohn Sidney McCainMulvaney aims to cement CFPB legacy by ensuring successor's confirmation Trump mocks McCain at Nevada rally Don’t disrespect McCain by torpedoing his clean National Defense Authorization Act MORE (R-Ariz.), who has debated both Romney and Obama, also weighed in on the presidential contest Sunday, saying both candidates are "excellent [debaters] in their own way."

But he rejected the notion that the debates would mark a dramatic turning point in the contest, arguing that the candidates will be so well practiced by Wednesday that game-changing remarks are unlikely.

"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," McCain said Sunday on CNN's "State of the Union" program. 

Still, the Arizona Republican predicted that Wednesday's debate would be one for the record books.

"I think you're going to see more viewers at this first debate than you have in history," he said.

Christie, for his part, is expecting fireworks from Romney.

"Every time he was backed into a corner in the primaries, he came out with a great debate performance because that's where he shines. And he's gonna do a great job on Wednesday night," Christie told CBS's Bob Schieffer. "Thursday morning, you're all gonna be scratching your heads saying, 'Wow, we have a barn-burner now for the next 33 days.'"