Stuart Johnson, Deseret News
President Barack Obama and Dave Cameron, Prime Minister of Great Britain, take in First Four action Tuesday.

DAYTON, Ohio — The opening round of the NCAA Tournament had a big-time atmosphere Tuesday night.

Not only was it one of the First Four games, but also President Barack Obama was in the house at University of Dayton Arena.

However, the Commander-in-Chief left the building before the nightcap of the doubleheader featuring BYU and Iona.

And he missed an amazing Cougar comeback, as BYU battled back from a 25-point first-half deficit to knock off the Gaels, 78-72.

The anticipated arrival of Obama, the nation's First Fan prompted tight security everywhere around the arena. And everyone went through the process of going through metal detectors and having bags searched. Signs were not permitted in the arena.

It seemed like around every corner there were Secret Service agents, dressed in suits, and police officers.

Obama and British Prime Minister David Cameron arrived just before tipoff of the first game featuring a pair of No. 16 seeds, Mississippi Valley State and Western Kentucky.

Obama, who wore a dress shirt and no tie, received a standing ovation as he arrived, and he was ushered to a front-row seat behind the basket. Later in the half, Obama and Cameron ate hot dogs and talked. Throughout the game, Obama chatted amiably with fans sitting nearby.

For Cameron, it was reportedly the first basketball game he had ever attended. Western Kentucky rallied from a 16-point deficit in the second half to defeat Mississippi Valley State, 59-58.

Alas, Obama didn't stick around to watch BYU, the alma mater of the man who he could face in November's presidential election — Mitt Romney.