In career mode, some fights are just too hard you don't have any choice but to loose, well, I solved this problem.
All you gotta do is turn off the auto save. Turn it off, because if you sign a contract with a fighter that you can't beat, you can come back in the game and sign a contract with a weaker fighter, all you have to do is save after every match you win.
In career mode go to options and turn illegal blows off. Make sure you equip the elbow shot and use it to easily cut the eye of your opponent. Keep punching and elbowing the same area. You will not be disqualified and it's easy to get the fight stopped and win by TKO.
Amateur; 10 undefeated fights.
Professional; 30 undefeated fights.