GREENSBORO, N.C. — With the game on the line and in need of a 3-pointer, Maryland put the ball in the hands of the Atlantic Coast Conference’s player of the year.

Somehow — and against the instructions from his coach — Iman Shumpert took it away from him.

Shumpert scored 14 points and made the key defensive play on Greivis Vasquez that lifted Georgia Tech past the 19th-ranked Terrapins 69-64 on Friday night in the quarterfinals of the ACC tournament.

“We actually wanted to foul there,” coach Paul Hewitt said. “He just stepped up and made a big-time defensive play.”

Maurice Miller added a season-high 13 points for the seventh-seeded Yellow Jackets (21-11). They blew most of a 19-point lead and had 25 turnovers, but for the second straight night, they did just enough to advance — this time, to the semifinals for the first time since 2005.

Vasquez had 17 points on 6 of 21 shooting for the second-seeded Terrapins (23-8), who had the ball and were within one possession of the lead six times in the final 4:30 and didn’t score on any of those possessions.

“We had a bunch of chances,” guard Eric Hayes said. “It’s a little frustrating when you use that much energy to get back into the game and get to two points and you just can’t really get over the top.”

The last chance came when Maryland trailed 67-64 and Vasquez pulled up for a long 3-pointer with about 6 seconds left when Shumpert stripped the ball from him.

“I figured he was going to try to get a foul on me,” Shumpert said. “I just kept replaying in my head that last time he made a big shot against us. I figured if he showed the ball I would deflect it. What I tried to do is deflect it up instead of smacking it down.”

Vasquez said Shumpert slapped his hand, “but we’re not the referees.”

“I should have maybe drove, but it was a tough call,” Vasquez said. “I have been making tough shots. Didn’t happen this time.”

Shumpert took off downcourt and was fouled, and he and Derrick Favors each hit one free throw in the final 3.7 seconds to seal the Yellow Jackets’ first victory in the series since 2004.

Favors finished with 11 points and 11 rebounds and Zachery Peacock added 11 points for the Yellow Jackets, who sent an already jumbled ACC bracket into further disarray. Entering Friday night’s finale between North Carolina State and third-seeded Florida State, four of the top six seeds were knocked out during the first two days.

Landon Milbourne had 15 points and Hayes added 14 for Maryland. The ACC’s hottest team and its regular-season co-champion nearly staged one of the biggest second-half rallies in the storied history of its league tournament, but ultimately had its seven-game winning streak snapped.

Gani Lawal finished with 11 rebounds for Georgia Tech, which took a critical five-point lead with 1:19 remaining after benefiting from a questionable non-call by the officials. With the shot clock winding down, Miller drove the lane and flung a shot that ricocheted off the glass — but did not appear to touch the rim — and Favors grabbed the ball out of the air and dunked it, making it 64-59. Television replays indicated the shot clock expired before the dunk.

Williams said the officials told him they thought the shot beat the buzzer, and official Karl Hess later told a pool reporter that it was a judgment call that was not reviewable.

“It looked good to me,” Hewitt said, breaking into a smile.

Georgia Tech held a 38-30 rebounding advantage and shot nearly 56 percent for the game to Maryland’s 37 percent — but the Terrapins did attempt 24 more shots than did the Yellow Jackets.

The Terrapins, who trailed 41-22 in the final minute of the first half, got themselves back in the game with a 22-5 run. Adrian Bowie started the rally with a three-point play with 1.7 seconds left before the break, and capped it with a layup that made it 46-44 with 13:41 to play. In between, Maryland forced 10 turnovers on Georgia Tech’s first 13 possessions of the half.

“We just weren’t strong with the ball,” Shumpert said.

This matchup featured all three of the ACC’s major award winners, with Maryland’s Vasquez, the player of the year, and Williams, its coach of the year, going up against Favors, the rookie of the year. Maryland won the previous matchup 76-74 on a buzzer-beating 3-pointer that came moments after Favors put Georgia Tech up by one.

For a while, it looked as if Favors and his teammates had decided this one much sooner, shooting nearly 62 percent in the first half and taking a 38-19 lead with 2 1/2 minutes before the break.

“The second half typifies the type of people who are playing for us this year,” Williams said. “I have to take responsibility for the way we played the first half. Whatever we did to get ready for this, obviously we had plenty of time to get ready, and we weren’t ready emotionally.”