Donald Trump

Republican presidential candidate, businessman Donald Trump addresses supporters at a campaign rally, Monday, Dec. 21, 2015, in Grand Rapids, Mich.

(Carlos Osorio | The Associated Press)

Billionaire businessman Donald Trump says he won the first Republican primary debate of 2016. How does he know? The longtime front-running candidate pointed to a syracuse.com reader poll in which 76 percent of voters said he was the winner.

Trump also cited polls from Drudge, Slate, Heavy.com and other sources, all showing him with a clear lead over his opponents in Thursday's GOP debate. He posted this graphic on Facebook.

Some GREAT polls that show that we won last night’s debate easily. If elected, I will win for AMERICA! #TrumpTrain #GOPDebate Posted by Donald J. Trump on Friday, January 15, 2016

The results of the poll in question have shifted since Trump's campaign spotted it, and now show 66 percent of voters supporting him. That's still a significant lead over his closest competitor, Ted Cruz, who was the winner according to 13 percent of voters.

To be clear, the syracuse.com poll is a basic opinion poll, and was not conducted using any scientific methods. Anyone who sees it can vote in the poll once, and the poll remains open for several days.

Still, there were more than 7,500 votes cast in the poll, nearly 5,000 of which went to Trump.

Trump squared off with Ted Cruz in several tense exchanges on Thursday night. Cruz accused Trump of having "New York values," but the businessman fired back that he was proud of New York values, citing New York City's response to the 9/11 terror attacks.

Trump also questioned Cruz's Canadian birth, wondering if he was eligible to run for president. Cruz dismissed the idea, saying that Trump was only attacking his citizenship now because he was afraid of Cruz's gains in the polls.

Trump has repeatedly won syracuse.com's unscientific post-debate polls in December, November and October, though never by quite such a large margin as he did in Thursday night's poll.