Duke appeared to have the game in hand and was driving for the go-ahead score – and its first bowl victory since 1961 – but the final 80 seconds proved disastrous.
With the game tied at 34 and the Blue Devils positioning themselves for a winning field goal, running back Josh Snead fumbled at the Cincinnati 5-yard line with 1:20 left and Bearcats defensive lineman John Williams recovered.
Kay then connected with tight end Travis Kelce on an 83-yard touchdown strike down the middle with 44 seconds left for the go-ahead score.
Cincinnati (10-3) sealed it on the next series when Maalik Bomar came crashing into Duke quarterback Sean Renfree, forcing a deflection that Nick Temple returned 55 yards for a touchdown.
Renfree threw for 358 yards – another Belk Bowl record – for the Blue Devils, who finished at 6-7.
NO. 24 SAN JOSE STATE 29, BOWLING GREEN 20
In Washington, David Fales passed for 395 yards and two touchdowns as San Jose State completed a comeback season with a win over Bowling Green.
Fales, a junior who led the nation in completion percentage during the regular season, completed 33 of 43 passes at RFK Stadium.
Fales led the drive that set up Austin Lopez’s 27-yard field goal with 4:43 remaining, and De’Leon Eskridge’s 1-yard run with 2:34 left provided the insurance.
The Spartans finished 11-2 and are in the national rankings for the first time since 1975.
They capped the year with a seven-game winning streak for their first 11-win season since 1940, a remarkable turnaround for a program that was 1-12 just two years ago and led Colorado to hire away coach Mike MacIntyre earlier this month.
Bowling Green finished 8-5.