NahDanny via ko within 8
As @Willy Waffle said Berto's only been KO'd once, and he very much went out on his shield. Fought with basically one arm for 11 rounds and got a KD of JSK, with that one arm. Berto may be a lot of things, but fragile isn't one. Also in the classic Berto/Ortiz 1 he fought with a concussion from the first round, if I remember correctly.