Ben Carson celebrated his birthday on Friday, and part of his birthday fun included joking about his GOP rival Donald Trump dropping out of the race.

“I guess the best birthday present is I heard Donald Trump had dropped out,” Ben Carson joked at Heritage Action for America’s presidential forum in Greenville, South Carolina.

“Oh, wait a minute,” he added. “That was just for today.”

Donald Trump cancelled his appearance at the forum Ben Carson was attending, citing a business transaction that was delayed.

On Tuesday of last week, a New York Times poll showed Carson and Trump neck and neck.

Breaking News: Carson pulls nearly even with Trump in Times/CBS News poll http://t.co/e3b0FYdZsd

— The New York Times (@nytimes) September 15, 2015

Ben Carson actually defended Trump earlier this summer over his comment about Mexicans.

“What we really need to be talking about is how do we take care of our illegal immigration problem,” he said. “I’ve talked about that extensively. And the key thing is we have to secure all our borders—north, south, east and west.”

“And it doesn’t have to be a fence or wall,” Carson added. “That’s stupid. We have all kinds of electronic surveillance devices, drones, not to mention people. So we can do it. And then turn off the spigot that dispenses all the things that they are coming here to get. Then there won’t be any reason for them to do it.”

“I mean that’s pretty simple, and straightforward,” he said. “And I think everybody knows that. That’s there’s the ability to do it, there’s not the will to do it. It’s too juicy a political football.”

How long do you suppose Carson and Trump will run neck and neck? They certainly didn’t seem on equal footing during Wednesday’s debate. Which one will inch by the other in the next poll?

Do you see the Republican race standing a chance of coming down to a Carson-Trump duel or will Jeb Bush, Carly Fiorina, or one of the other candidates trump–no pun intended–them both?