Downey had 13 points in the first half in just 12 minutes, getting into the game while Gray sat out in foul trouble, leading Wake to a 41-25 halftime edge.
In the second half, Virginia Tech (12-8, 5-4 Atlantic Coast Conference) cut the lead to 50-43 with 13 minutes remaining. Then Downey hit the big 3-pointer with the shot clock winding down, silencing the sellout crowd at Cassell Coliseum. The Deacons (19-3, 7-2 ACC) sprinted out to a 64-43 lead, and the Hokies came no closer than 15 the rest of the game.
Wake Forest coach Skip Prosser called Downey's 3-pointer "the play of the game," but Downey said he had no idea his shot started such a streak.
"I'm glad it did. ... I still felt that they weren't going to go away just then," Downey said.
Virginia Tech coach Seth Greenberg thought his team played well to get back in the game until Downey hit the 3.
"We cut to seven and I thought we were back in the basketball game. We played a pretty solid possession and they kick it out for a 3," he said.
Gray finished with 16 points. Paul didn't score until hitting a free throw with 3:30 to go, finishing with three points and a game-high nine assists.
"If we're going to hold Chris Paul to three points, we can't let a guy off the bench get 18," Greenberg said.
Added Gray: "We feel like we've got a deep enough bench so that if one of our stars is not playing as well, our bench will come in and play well for us."
Eric Williams scored 14 and pulled down 12 rebounds for the Demon Deacons, who are tied for second place in the ACC with Duke.
For the Hokies, the loss ended a streak in which they had won five of their last six ACC games in their inaugural season in the league.
"I'm happy we're 5-4, but I know where we are and where we have to go. We have a long way to go," Greenberg said.
Virginia Tech struggled to keep up with the Demon Deacons' fast-paced offense, as Wake scored frequently on alley-oops and wide open 3-pointers. Wake shot 58 percent, including 61 percent in the first half.
"We set a lot of good screens and we got people open," Downey said.
The Hokies shot just 38 percent, including 28 percent in the first half, and went 2-of-13 from 3-point range in the game.
"Shot selection has a lot to do with it," Greenberg said.