Cooper made a pair of free throws at 2:34 for a five-point bulge.
But the Raiders didn’t score again after that, and Kent State dominated down the stretch to force overtime and then asserted itself in the extra session for a 76-72 victory.
After the Raiders took a three-point lead in the OT, the Golden Flashes went on an 8-0 run to notch their 16th straight win over Horizon League teams.
Cooper had 19 points, going 7 of 16 from the field, and Andrea Holden had a double-double off the bench with 10 points and 10 rebounds.
Solomon Callaghan followed a 20-point performance in a win over Radford on Saturday with 10 points as the Raiders fell to 2-3.
Having had the outcome seemingly in hand, the defeat will be hard to shake for the Raiders. Kent State (4-1) was picked third in the MAC preseason poll after going 24-12 last season.
The Raiders had a pair of turnovers in the final 1:52 of regulation, including a shot-clock violation, and Cooper missed a potential game-winning shot from the top of the key at the buzzer.
Wright State also had three technicals: two on TJ Burch (which Kent State converted into four points) and one on Callaghan (also a gift two points for the Golden Flashes).
After taking a 67-64 lead in OT, the Raiders were blanked on five straight possessions, allowing Kent State, which went 4 of 6 from the field in the five-minute period, to pull away.
Delrecco Gillespie, a 6-8 senior who went into the game averaging 19.8 points, had 26 on 10-of-17 shooting.
But the Wright State defense was solid for the second day in a row, at least through regulation.
Kent State, which had averaged 98.8 points in its first four games, made 25 of 62 shots (40.3%) and went only 5 of 23 on 3’s.
Wright State went 27 of 61 (44.3%) overall and 6 of 24 on 3’s.
The difference was at the foul line with the winners going 21 of 26 and the Raiders 12 of 19.
Next game
Who: Ohio Wesleyan at Wright State
When: 7 p.m. Thursday
Streaming: ESPN+
Radio: 1410-AM, 101.5-FM
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