According to American criminal procedure law, to convict a criminal suspect, all reasonable doubts must be ruled out. In other words, the prosecutor must have complete evidence and no mistakes, even if there is a little mistake, he can't be convicted. When the public prosecutor takes evidence, the procedure is illegal, that is to say, because the procedure of taking evidence is illegal, the court cannot accept the evidence obtained. In this case, if this evidence is excluded, the prosecutor's evidence will be incomplete and Simpson will not be convicted, so Simpson won the case.
According to the American Civil Procedure Law, the standard of winning a civil dispute is "high probability", that is, as long as most of the evidence is legal and reaches a high probability, the case can be won, instead of pursuing that all the evidence is adopted. As mentioned above, the evidence collected by the public prosecutor is legal and valid except one that is illegal and cannot be used. So the evidence can reach the standard of "high probability" in civil litigation, so Simpson's opponent wins and Simpson loses.