Smith scored 26 points, hitting 9-of-17 from the field and tying a career high with six 3-pointers. Virginia Tech (9-11, 1-6 ACC) snapped a seven-game losing streak and a five-game losing streak to the Panthers.
In overtime, the Panthers (13-8, 3-5 ACC), who lost their third straight, tied the game at 67 on Chris Jones' putback with 1:08 to play. Virginia Tech called a timeout with 47 seconds left, and Malik Muller missed a lay-up inside with 30 seconds to go. But the rebound went out of bounds off a Pittsburgh player, giving the Hokies another chance.
They held the ball before running a play that freed Smith for a 3-pointer from the top of the key.
Pittsburgh called a timeout and got a good look on its final possession, but James Robinson's 3-pointer hit the front of the rim and bounced away at the buzzer.
The Hokies trailed 60-53 after Robinson scored with 2:11 remaining in regulation. But Virginia Tech went on a 6-0 run. Christian Beyer's three-point play with 1:50 left cut the lead to four, and Smith's 3-pointer with 52 seconds to go made it 60-59.
A Robinson jumper with 19 seconds to go gave the Panthers a 62-59 lead. But Smith hit a long 3-pointer with two seconds left to tie the game and send it to overtime.
Malik Muller added a career-high 22 points for the Hokies, who shot just 38.3 percent from the floor, but tied a season high with 12 3-pointers, of which Muller hit four.
Virginia Tech played its fourth straight game without leading scorer Justin Bibbs (13.6 per game). Bibbs has been out with a concussion...Virginia Tech's freshmen have played more than 50 percent of the team's minutes this season, the highest percentage in the ACC.
Entering the Pittsburgh game, Virginia Tech had played four straight games against teams ranked in the top 20. No ACC team had done that since the 2001 NC State team.
Virginia Tech's halftime lead, 29-24, against Pittsburgh marked its first in seven games.
Pittsburgh's Michael Young had scored in double figures in 11 of the previous 12 games, but didn't score his first point until the 17:00 mark of the second half and finished with six points.
Pittsburgh has won just one true road game this season after going an ACC-best 7-2 on the road last season.
Virginia Tech plays at Wake Forest on Saturday
Pittsburgh hosts No. 8 Notre Dame on Saturday