"The next morning, on Fox News, my job - my mission - was to send a very strong signal of strength".
Navarro now regrets the "inappropriate" language he used, he admitted at a Wall Street Journal event on Tuesday.
"And that's what bad faith Justin Trudeau did with that stunt press conference", he added Sunday, noting his comments came "right from Air Force One".
President Trump is accusing the country's prime minister of making false statements, and the president's trade adviser saying there's "a special place in hell" for the leader of Canada, our biggest trading partner in all of the world, our best friend from way back in World War II and every time in between.
"I will always protect Canadian workers and Canadian interests", Mr Trudeau said.
The White House's chief economic adviser, Larry Kudlow, similarly told CNN on Sunday that Trudeau "really kind of stabbed us in the back". The move has been roundly criticized by Canada and the European Union, leading to heightened tensions at last week's summit of the Group of Seven wealthy democracies - just before Trump left for Singapore and a meeting with North Korean dictator Kim Jong Un.
"That's going to cost a lot of money for the people of Canada; he learned", Mr Trump said wagging his finger.
Trump issued a statement on Tuesday in which he promised Trudeau's statements would end up costing Canada "a lot of money".
The communique - which had appeared to have papered over the cracks that surfaced at the summit - said the leaders of the US, Canada, Britain, France, Italy, Germany and Japan agreed on the need for "free, fair, and mutually beneficial trade" and the importance of fighting protectionism.
"Let me correct a mistake I made", he said at the conference.
Canadian officials have stressed the two countries' extensive trading relationship and pointed out that Canada is the top export destination for 35 U.S. states and that 9 million jobs in the United States depend on trade with its northern neighbour.
"I see the television and he's giving a news conference about how he "will not be pushed around" by the United States".
The Trump administration is proceeding with plans to impose tariffs on at least $50 billion of Chinese goods over accusations of intellectual property theft.