Radford celebrates Rashun Davis’s decisive three-pointer in its upset of Georgetown. (John McDonnell/The Washington Post)

It was difficult for Georgetown Coach John Thompson III to explain what unfolded at Verizon Center on Saturday afternoon. His team’s season-opening game against Radford was supposed to be a routine tuneup. For nearly three hours, the game instead descended into a chaotic thriller. It didn’t relent until Radford’s Rashun Davis drained a game-winning three-pointer with 0.7 seconds left in the second overtime to lift his team to an 82-80 win.

A stunned Thompson and his players, some of whom put their hands on their heads as if the loss ended their season, were forced to confront some uncomfortable questions. At the forefront: Was Georgetown looking ahead to Tuesday night’s showdown with No. 3 Maryland?

“I don’t think so. I don’t know,” Thompson said. “We’ll go back and we’ll talk about it, but I told this group every single game on the schedule is tough.”

There will be little time to reflect, but when the Hoyas do, they will conjure images of the final minute of the second overtime, when they failed to protect an 80-79 lead and watched as Davis pulled up for the game-winner.

Rashun Davis, shown rising for the game-winner, scores a game-high 28 points. (John McDonnell/The Washington Post)

Senior guard D’Vauntes Smith-Rivera finished with 15 points, and senior center Bradley Hayes added 19 points and 12 rebounds for Georgetown, which battled back from a five-point deficit in the final minute of regulation to tie the game at 64. It did the same in the first overtime, as Smith-Rivera tied it at 71 with 27 seconds remaining to extend the game. But in the end, the Hoyas were left with about 72 hours to pick up the pieces and prepare for the Terrapins in College Park.

“We learn from it,” Hayes said. “We go back and we watch film, see what we did wrong and get ready for Maryland on Tuesday.”

Davis, a 5-foot-11 senior, finished with a game-high 28 points on 12-of-19 shooting for the Highlanders, who outrebounded the Hoyas 43-37 despite playing no one taller than 6-8. They also avenged a 76-49 loss at Georgetown last December.

“He’s one tough nut,” Thompson said of Davis, adding that both teams could have easily packed it in when the game turned into a grind in the second half. Georgetown trailed 64-59 before Isaac Copeland nailed a three-pointer with 33 seconds remaining in regulation. That allowed the Hoyas to set up the press. After the ball was inbounded to Davis, L.J. Peak simply muscled his way for a steal under the basket and scored as Davis fouled him out of frustration.

“We were down. We were pressing and had to get up into [Davis], and so he turned it over,” Thompson said. “One of the few mistakes he made the whole night.”

But Peak missed the ensuing free throw and the game went to overtime. Georgetown made 19 of 20 free throws in the first half but just 4 of 12 after that.

Hayes gave Georgetown a 68-65 lead with three minutes remaining in the first overtime with consecutive baskets, including a thunderous dunk off a feed from Copeland. That ignited the crowd at Verizon Center, but Radford seemed to welcome the chaos. Guard Cameron Jones (20 points) and Davis each chipped in a layup on consecutive possessions to take back the lead 69-68 with 2:17 remaining in the extra frame, and after Copeland missed a go-ahead three-pointer after a timeout, forward Brandon Holcomb used a hook shot to extend the lead to 71-68.

After hitting a foul shot to cut the lead to two, Smith-Rivera tied the game with a steal and layup with 27 seconds remaining. Georgetown then set the table for a dramatic finish after Radford threw the ball away on the ensuing inbound, and Peak held the ball for a final shot. He eventually dumped the ball to Copeland, whose corner three-point attempt rattled in and out.

The teams continued to trade blows throughout the second overtime. Smith-Rivera made consecutive layups to give the Hoyas a 80-79 lead with 1:44 remaining, and Radford looked as if it had finally cracked after Davis missed two free throws on the next trip.

But instead of holding the ball on the ensuing possession, Peak elected to shoot a wide-open three-pointer and missed with nine seconds to go. That set into motion the game-winning three-pointer by Davis, who celebrated by backpedaling past the stunned Georgetown bench.

“They just wanted it more than we did in the moment,” Hayes said, “and it’s just that simple.”