It started out well for Ted Cruz, surging in the polls, a commanding presence on the Republican debate stage with just over two weeks until the Iowa caucuses where he's battling it out for first place with Donald Trump.
Trump has been the leading voice questioning Cruz's Canadian birth - Cruz was ready.
"I recognize that Donald is dismayed that his poll numbers are falling in Iowa. But the facts and the law here are really quite clear," said Cruz.
It began to unravel for Cruz when he was asked to explain what he means when he describes Trump as having quote, "New York values."
"Everyone understands that the values in New York City, are socially liberal or pro abortion or pro gay marriage, focus around money and the media," said Cruz. "And I guess I can frame it another way, not a lot of conservatives come out of Manhattan. I'm just saying."
Trump responded by saying, "Conservatives actually do come out of Manhattan including William F Buckley and others just so you understand."
Trump went on to describe New York as a great place with loving people who rallied together on 9-11 in a way that moved the entire world.
"When the World Trade Center came down, I saw something that no place on earth could have handled more beautifully, more humanely than New York," Trump said. "Everybody in the world watched and everybody in the world loved New York and loved New Yorkers and I have to tell you that was a very insulting statement that Ted made."
Boston University Professor Thomas Whalen thinks Cruz significantly hurt his chances against Trump in that one exchange while at the same time allowing Trump to elevate his status in the GOP. "I think it's a major game changer for Donald Trump, probably his finest moment in the campaign," he said.
Even the Democrats had praise for Trump.
New York City Mayor Bill De Blasio tweeted: Just this once, Trump's right: New Yorkers value hard work, diversity, tolerance, resilience, and building better lives for our families.
Hillary Clinton tweeted: There is ONE thing I agree with @realDonaldTrump on: his love for NYC. Appreciated his tribute to our city's heroic response to terrorism.