You take a full grown wild canine that has been fighting & killing to survive it's whole life & it isn't gonna be much of a contest between a wild animal & a domestic dog...I don't care how BADASS you THINK he is...
Wolves actually don't do much if any real fighting. They try to have the odds stacked substantially in their favor when they pursue game, and amongst themselves their fights don't amount to much, since the pecking order is held fairly stable. Winners and losers in their fights are determined quickly, and mostly after a lot of harmless threat display and posturing, rather than real gripping.
Think about it. Were it otherwise, wolves in the wild (both fight winners and fight losers) would be constantly dealing with bite wounds, and bite wounds in the wild tend to become infected and kill those that have them. This would tend to prevent the determined-fighting characteristic that you believe they possess from passing on to the next generation.
