Duran gets it bad, I guess because it was such a high profile fight.

But out of the thousands of matches, I'm a bit stumped. Regardless of cherry picking and mismatches, I am hard pressed to name fighters that flat out quit.
Only one comes to mind is Erik Morales Manny Pacquiao III.

El Terrible sat on his bum, winced, no pain, just flat out quit. Is quitting a rare occurrence, or am I drawing a blank?