Lewis-McCall Morrison-Bentt Judah-Baldomir, this might have been a mandatory but Judah was a huge favorite and had already hammered out a deal to fight Mayweather after this. Jones-Green Morales-Raheem
First one I thought of. Tommy was supposed to fight Lennox right after that "tune up", got sloppy, and Bentt made him pay for it. A microcosm for The Duke's career right there- comes off likely the best boxing performance of his career vs Big George only to get knocked out by Michael Friggin' Bentt. A bunch of good examples have already been brought up. Ones I haven't seen mentioned yet: Tszyu-Phillips, and perhaps the best example, Ali-Spinks.