The ACC's Rookie of the Year had the highest-scoring game in the tournament by any player regardless of class since 1970 and broke the old mark of 40 set two years ago by North Carolina's Harrison Barnes.
He was 14 of 18, made his final 12 shots and was a one-man show in bringing the eighth-seeded Eagles (16-16) back from an early 15-0 deficit and into a Friday quarterfinal against No. 9 Miami, the tournament's top seed.
Marcus Georges-Hunt had 21 points and 11 rebounds to lead the ninth-seeded Yellow Jackets (16-15), who have lost five of seven and now are likely left to hope for an invitation to the NIT.
Hanlan's eight 3-pointers — one shy of a tournament record — matched the second most by any player in the history of the event.
He scored 25 points during the 37-10 run that flipped BC's 14-point deficit into a 13-point lead, 51-38 with 14:41 remaining, and put the Eagles well on their way to just their second ACC tournament victory since 2009.
The only drama down the stretch was whether he'd catch Barnes — or even Lennie Rosenbluth's 56-year-old record of 45 points for any player regardless of class.
He passed Barnes with about 2:45 left when he took a kick-out pass from Ryan Anderson on the left wing and launched an open 3-pointer that circled the rim and clipped the backboard before dropping through.
He exited for good with 2:13 remaining, bringing an end to the eighth 40-point performance in tournament history and the highest-scoring game since North Carolina's Charles Scott had 41 in the 1970 quarterfinals.
Joe Rahon had 15 points and Anderson added 11 points — including a behind-the-back drive down the lane and past Robert Carter Jr. for a dunk that would have been the signature highlight in any other game.
The opening game of the tournament matched two of the youngest teams in the league.
Eleven of the 14 players on BC's roster are freshmen or sophomores — including Hanlan — while the Yellow Jackets start three freshmen around Udofia, the lone senior on their team — and the rookies certainly stole the show in this one.
These young Eagles — the preseason pick to finish last in the league — finally figured out how to win down the stretch. They came to Greensboro on a three-game winning streak and claimed their second win over Georgia Tech in a six-day span.
It looked like Georges-Hunt — the only ACC freshman to lead his team in scoring — would be the best rookie on the court early, hitting two early 3s to help the Yellow Jackets race out to a short-lived 15-0 lead.
Then, Hanlan took over — and the Eagles dominated the rest of the way.