Has a fighter ever lost the 'formality' rematch or career defining win?

[ICB]

Mosley's defeat to Vernon Forrest. Shane looked unbeatable prior to this.

If you're talking about formality fights where someone played spoiler, then Jimmy Young, Carlos Baldomir & Zahir Raheem have all done this to George Foreman, Zab Judah & Erik Morales respectively.

Kind of but only when they did it twice, I guess Forrest could count against Shane, but I'm not sure he was that big an underdog in the second fight at least.

A hypothetical example might be Lennox Lewis losing to Rahman again in the rematch, or Wlad being knocked out again by Lamon Brewster.

Pavlik Hopkins is a good example of the unbeaten heir elect losing to the supposedly retirement bound former champ.

Michael Spinks vs Larry Holmes, im pretty sure Michael Spinks was the underdog in both fights.

Or how about Iran Barkley vs Tommy Hearns ?

[Kev]

Mosley's defeat to Vernon Forrest. Shane looked unbeatable prior to this.

If you're talking about formality fights where someone played spoiler, then Jimmy Young, Carlos Baldomir & Zahir Raheem have all done this to George Foreman, Zab Judah & Erik Morales respectively.

Kind of but only when they did it twice, I guess Forrest could count against Shane, but I'm not sure he was that big an underdog in the second fight at least.

A hypothetical example might be Lennox Lewis losing to Rahman again in the rematch, or Wlad being knocked out again by Lamon Brewster.

Pavlik Hopkins is a good example of the unbeaten heir elect losing to the supposedly retirement bound former champ.

Michael Spinks vs Larry Holmes, im pretty sure Michael Spinks was the underdog in both fights.

Or how about Iran Barkley vs Tommy Hearns ?

Yeah good calls Ice.