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Donald Trump opened debate by boasting about the size of his genitals

Debate came as the GOP field is quickly winnowing

Detroit CNN  — 

The Republican presidential race got dirty Thursday night.

Donald Trump opened the GOP debate here by boasting about the size of his genitals. He responded to recent comments from Marco Rubio in which the Florida senator joked about the size of Trump’s hands and said “you know what they say about men with small hands.”

READ: Donald Trump defends size of his penis

On the debate stage, Trump stretched his hands out for the audience to see – then insisted the suggestion that “something else must be small” was false.

“I guarantee you there’s no problem,” Trump said to howls from the audience at the Fox debate.

It was perhaps the most surreal moment yet in a presidential race that has already been dominated by unprecedented drama and personal attacks. Trump went into the debate after spending the day in a heated war of words with the party’s 2012 nominee, Mitt Romney.

Romney, who has blasted Trump for days, delivered a sharp condemnation of Trump earlier Thursday – a deeply unusual move for a former presidential nominee.

READ: Opinion - Debate embarrassing to watch

“Here’s what I know: Donald Trump is a phony, a fraud,” Romney said in a speech in Salt Lake City. “His promises are as worthless as a degree from Trump University. He’s playing members of the American public for suckers. He gets a free ride to the White House, and all we get is a lousy hat.”

He hit back during the debate, calling Romney an “embarrassment” to the GOP.

“He was a failed candidate, he should have beaten President Obama very easy. He failed miserably and it was an embarrassment to everybody,” Trump said. “I guess obviously he wants to be relevant, he wants to be back in the game.”

READ: Most memorable insults

During a rally in Maine earlier Thursday, Trump blasted Romney for “begging” for his endorsement.

“I don’t know what happened to him,” Trump said. “You can see how loyal he is. He was begging for my endorsement. I could have said, ‘Mitt, drop to your knees.’ He would have dropped to his knees.”

With Trump emerging as the undisputed GOP front-runner, many party leaders and insiders insist he’s not a true conservative. They also worry that Trump’s inflammatory rhetoric on immigration could permanently unravel the GOP’s efforts over the years to reach out to Latinos and other minorities.

But even as Romney and others try to lead the effort to stop Trump, the belated push may only reinforce the real estate mogul’s appeal as his supporters have already shown their deep loathing for establishment figures.

Amid the GOP establishment’s revolt against Trump, all three of Trump’s rivals pledged on the debate stage to support the party’s eventual nominee even if that ends up being Trump.

Trump, who has repeatedly threatened the possibility of launching a third-party bid should he feel that the party is treating him unfairly, also said he would back whoever the party crowns.

“The answer is, yes, I will.”

Winnowing GOP field

The debate comes as the GOP field is quickly winnowing. When Trump took the debate stage for the first time in August, 17 candidates were seeking the Republican nomination. Eight months later, Trump is the undisputed front-runner and is on stage with just three rivals: Rubio, Ted Cruz and John Kasich.

The candidates met two days after Trump dominated the Super Tuesday contests, notching seven victories and picking up hundreds of new delegates. Cruz, who kicked off the GOP primary season by winning the Iowa caucuses, added three victories on Tuesday, including in his delegate-heavy home state of Texas. Rubio also got his first win of the season, coming in first in Minnesota’s caucuses.