This is generally the way it is (not always): You have a Rottweiler, you train it to be a fighting dog, it would generally be able to take any dog not without training (and some that are trained), although this isn't always the case, it usually is. If you train a Pitbull (of any sort) to be a fighting dog, basically the same way you would a Rottweiler, and the Rottweiler and the Pitbull fight, 9 out of 10 times, the Pitbull's going to come out better than the Rottweiler. This is because they are bred for fighting. Pitbulls are crosses between bulldogs and terriers, originally bred for fighting. They don't do any other job particularly well.

But there are exceptions.