With the fates of their campaigns on the line next week, senators Marco Rubio and Ted Cruz focused all their firepower on front runner Donald Trump in the latest Republican debate - for the first time making a concerted effort to attack the billionaire on everything from his ethics to his conservative values and grasp of issues.
The result was the most explosive debate the party has held so far. The trio traded blows throughout, interrupting one another with barbs and insults. The event frequently devolved into shouting matches that moderators struggled to rein in.
This was a night when substance was overshadowed by the joint effort by the second- and third- placed candidates to try to derail the momentum of the front runner before next week's so-called Super Tuesday voting. The stakes are especially high for Mr Cruz and Mr Rubio, who each are trying to convince anti-Trump voters that they stand the best chance of stopping him.
Tuesday is the most important day of the primary calendar as 11 states cast their votes for the party nominee. Mr Trump leads in all but one of those states - Mr Cruz's home state of Texas. The property mogul has decisively won three of the four contests so far.
While the arguing made for entertaining viewing, analysts question if the attacks have come too late to hurt the Trump campaign.
Said Mr Aaron Kall, director of debate at the University of Michigan: "His (Mr Trump's) supporters are extremely loyal and have not penalised him for inconsistent debate performances so far. Rubio scored his second winning debate performance in a row after a disastrous New Hampshire outing and it will be interesting to see how tonight alters the trajectory of the Republican race heading into the Super Tuesday primaries next week."
The knives were out on Thursday night right from the first question on immigration.
Mr Rubio quickly brought up a 1983 lawsuit, where 200 undocumented Polish workers working on Trump Tower in New York sued Mr Trump for cheating them out of their wages. He then referenced it relentlessly, including when the immigration issue turned to Mr Trump's proposal to build a wall between the US and Mexico.
"If he builds the wall the way he built Trump Towers, he'll be using illegal immigrant labour to do it," Mr Rubio interjected. "Such a cute sound bite," Mr Trump retorted.
Mr Rubio tried to subject Mr Trump to the same uncomfortable treatment he had received from Governor Chris Christie in a debate earlier this month. The governor had flustered Mr Rubio, who ended by repeating the same point a few times.
When Mr Trump repeated an answer on his healthcare plan on Thursday, Mr Rubio jumped in: "Now he's repeating himself."
Mr Trump: "I watched him repeat himself five times four weeks ago."
Mr Rubio: "I just watched you repeat yourself five times five seconds ago."
As for Mr Cruz, his attacks largely stayed true to his key message of being the most consistent conservative and argued he would fare better than Mr Trump against former secretary of state Hillary Clinton.
"We've got to win this election, and we can't do it with a candidate who agrees with Hillary Clinton and can't take it to her and beat her on the debate stage and at the polls," said Mr Cruz.
When Mr Trump then brought up how he is running ahead in Republican polls, Mr Cruz attacked again: "But you're not beating Hillary."
That led to Mr Trump's line of the night: "Hey, if I can't beat her, you're really going to get killed, aren't you?"
The bickering left little time for Governor John Kasich and Dr Ben Carson to make a mark.
