player ratings

I want to make an own roster with unrealistic stats. Some of the players shall be very good offensive while other suck completely in their defensive skills.
I've tried to putt all players of a team with the lowest skills possible and let them play against a team with highly skilled players but the best team didn't won
ba far.

My question is:
what attributes must a player have to be so weak in defence that other player can dunk on?