Kerry Blackshear Jr. turned an offensive rebound into a layup with five seconds on the clock to give Virginia Tech (18-7, 7-5) the lead and ultimately the win.
The Cavaliers were down by four points with under a minute to play in regulation, but sent the game to overtime with back-to-back baskets from sophomore Ty Jerome.
"We nearly stole that game but that's what it would have been ... stealing", said UVa coach Tony Bennett, whose Cavaliers (23-2, 12-1 ACC) had won 15 games in a row since a December 5 loss at West Virginia.
The pack-line defense has shown very little holes, as opposing offenses have scored double-digits less than their single average and fail to find an answer for Virginia's lethal backcourt trio of Ty Jerome, Guy, and Devon Hall.
The Cavaliers seemed a likely new No. 1 after No. 1 Villanova lost this week to St. John's.
Now the Hokies are 6-5 in ACC play, good for seventh in the league and are coming off a 10-point win over North Carolina State.
2 killed when Turkish helicopter crashes in Syria
An army statement said a team of investigators is carrying out a "technical investigation". Seven Turkish civilians have also lost their lives.
Virginia Tech also made 11 three-pointers and shot 43.1 percent for the game. You can sign up for a free 7-day trial no matter what package you choose, plus you can either get a free Amazon Fire TV if you prepay two months, or $25 off your first month with promo code "YESNOW".
In the first meeting this season back in early January, Virginia held the Hokies to a season-low 52 points in a 26-point win in Blacksburg, Va.
Virginia's success this season can be attributed to the team's defense. One of them, Purdue, was playing at Michigan State, themselves a top-5 team, so that wasn't so much an upset. Virginia Tech has a lot to play for, as they want to make a push towards the postseason and a higher seed so they are not matched up against tougher foes early.
Hall, shooting 93.4 percent from the free-throw line for the year, missed the second of two free throws; then, after a 3-pointer by Tech's Nickeil Alexander-Walker cut the deficit to 60-59, Hall was fouled again.
BlackshearRobinson had a chance to put the Cavaliers in real trouble, but missed the front end of a one-and-one with 20.6 seconds left and the Hokies ahead 49-47. Blackshear finished with seven points, going 3 for 10 from the field and missing all six of his 3-point attempts, but that was all forgotten after his game-winner. It was the Hokies' best defensive field goal percentage allowed against an ACC opponent and Virginia's worst shooting night of the season.
The Hokies shot 57 percent overall (12-21) and 57 percent from 3-point range (8-14) in the first half, at one point reeling off 17 straight points to open a 22-13 lead.