The raucous debate capped a day that saw the Republican's most recent presidential nominees, Mitt Romney and John McCain, lambasting Trump, the current front-runner.
After days of literally below-the-belt mudslinging on the campaign trail, Ted Cruz's apparent mission at Thursday's GOP presidential debate in Detroit was to rise above the fray and raise doubts about frontrunner Donald Trump's temperament.
Fox News anchors Megyn Kelly, Bret Baier, and Chris Wallace are set to moderate, and Romney will surely come up in discussion during the course of the debate, whether they initiate the conversation or another candidate strikes first.
Mainstream figures in the party have been seeking a strategy to halt Trump's march to the nomination for the November 8 election to succeed Democratic President Barack Obama.
Trump is looked upon unfavourably by the Republican party he seeks to represent, largely because of his erratic policies and tendency to attract controversy. When the OH governor meets with voters, he said, "you know what they really want to know?" He dismissed any suggestion he might be small elsewhere, Trump said: "I guarantee you there is no problem".
Thursday's debate was the first time he faced questioning from Kelly since the two clashed in the first primary debate.
"The last person that Hillary Clinton wants to face is Donald Trump", he declared at the Fox Theatre in Detroit Thursday night.
Trump said he was starting to do that, but defended that and other business decisions he'd made.
Rubio justified his attacks on Trump by saying the billionaire businessman had "basically mocked everybody" over the past year.
Theo Wargo NBC
Trump disparaged Romney in a series of tweets, including: "I am not a Mitt Romney, who doesn't know how to win".
No, we're not talking about Ted Cruz.
Ohio Gov. John Kasich made it unanimous.
Rubio has been denouncing Trump on both policy and personal grounds as he tries to emerge as Trump's chief rival.
"This little guy has lied so much about my record", Trump responded, adding that he had begun bringing some clothing operations home from overseas.
Trump said it was a minor civil suit he wasn't settling on principle.
"Let's see what happens at the end of three years", Trump said.
Cruz, as he has done for weeks, also seized the spotlight to hit Trump for having supported and donated money to Democrats in the past. After Super Tuesday, Marco Rubio called for emergency collective action by the remaining contenders to stop the "con man" Trump without adjudicating for the present which of them would win the prize.
Mr Rubio excused his own attacks by essentially saying it was Mr Trump, who first opened the flood gates.