KO Magazine's previous Upset of the Year was Roger Stafford over Pipino Cuevas. A year later they wrote something along the lines of, "Laing in victory is not the fighter Stafford is. Cuevas in defeat is not the fighter Duran is. If Stafford over Cuevas is an upset, then what does that make Laing over Duran?"
I viewed the live broadcast of both bouts. I do think Laing-Duran was the biggest upset I watched during my time following boxing. Retroactively, we know Hearns had taken Pipino's chin away when the featherfisted Stafford dropped him, but Duran had an unbelievable amount still left in the tank.
As a postscript concerning Roger Stafford, I was as hardcore an SRL hater as there was, but Ray was very highly motivated by Stafford's big mouth and training hard with high motivation when he abruptly announced his retirement. But before that happened, I was actually rooting for SRL to beat the shit out of Stafford, and I hadn't rooted for SRL since the Olympics.