Which boxer has defeated the most undefeated fighters?

mike tyson beat 7, as did nicolai valuev. but those include novice wins.

EDIT

larry holmes has wins over 10.

http://boxrec.com/forum/viewtopic.php?f=4&t=146773

Hard to say for sure for there could be a number of them in the past and even now. There's Sugar Ray Leonard who beat then undefeated Wilfred Benitez, Tommy Hearns and Ayub Kalule in title fights at 147 and 154 lbs. There's Roberto Duran who pinned first losses to Leonard and Davey Moore. There's Bernard Hopkins who inflicted first losses to Tito Trinidad and Kelly Pavlik. And there's Floyd Mayweather who beat Ricky Hatton and Canelo Alvarez for their first career losses..

Impossible to say. Most fighters have most of their victories against undefeated fighters early on in their career. Felix Verdejo already beat an undefeated Mexican in Lauro Alcantar yet none of them even have or have had paper titles.