ECU trailed the visiting Savannah State Tigers for the first thirty-nine minutes at Minges Coliseum, before senior point-guard Miguel Paul drained a three-pointer to give the Pirates their first lead at 64-63 with 47 seconds to go.
Savannah State had an opportunity to salvage a road victory in the final seconds, but junior Akeem Richmond snuffed out the chance and the Tigers were unable to get a shot off.
The Pirates (19-12) escaped 66-65 for the program's first postseason tournament win in five attempts since becoming a Division-I school.
"I don't really know how we won that game to be honest," said ECU coach Jeff Lebo. "This team, when they look around at each other, will get to say that they were the first (to win a postseason game).
Richmond added, "It's an amazing feeling, we made history tonight. It's all about surviving and advancing.
The Pirates will host another game in the second round of the CIT on Saturday at 5 pm. The opponent has yet to be determined.
Savannah State (19-15) raced out to a 14-3 lead to begin the uphill battle for the Pirates. The Tigers led by as many as fifteen points at 30-15 following a monster put-back jam by Jyles Smith.
ECU would respond with a 10-0 run that was snapped on a buzzer-beating jumper by Deven Williams to put SSU ahead 32-25 going into the locker room. Williams had 13 of his team-high 18 points in the first twenty minutes.
Savannah State opened the second half by outscoring the Pirates 11-3 and would eventually duplicate its largest lead of the game at 45-30 with 14 minutes left to play.
ECU senior forward Maurice Kemp would keep the Pirates afloat by scoring the team's first eight points of the half and played a huge role in a 20-9 run that put them within striking distance down the stretch.
Kemp had a game-high 21 points to go along with his nine rebounds, six assists, four steals and two blocks.
Paul was held off the score sheet until he hit a pair of technical free throws with 8:51 left in the game, but scored the Pirates' final five points to seal the win. His last minute go-ahead triple was generated on a broken play that nearly didn't happen.
"I almost called timeout," said Lebo. "Sometimes you get a three when you're disorganized, so I just went with it.
Paul finished with 10 points and a game-high 9 assists.
After shooting a porous 7-for-24 from the field going into the locker room, ECU hit fifty percent of its attempts in the second half (12-for-24).
Richmond continued his tear from beyond the three-point arc by draining four of his eight outside-shots for 14 points off the bench.
ECU senior guard Shamarr Bowden scored four points in his seven minutes after missing the last six games with a shoulder injury.
Robert Sampson had nine points and a game-high 14 rebounds.