Confused about the question. What is it trying to say? Would the sophists argue with Socrates on justification?
A passage from Alexander Nehamas may help :
Socrates may well have claimed that his purpose in argument was always the discovery of the truth. But if, as I have argued, the test of truth in the elenchus is essentially dialectical, then the truth can be established only to the extent that you continue to win the argument? and it can therefore be tested only negatively: the fact that you have so far been victorious in your argument with me does not in any way guarantee that a new consideration under-mining your position will not be found. Both Socrates and his opponents, therefore, necessarily aimed at victory. In this respect at least, Socrates cannot have differed in method from those sophists who practiced the method of question-and-answer and who did not intentionally use fallacious reasoning. (A. Nehamas, 'Eristic, Antilogic, Sophistic, Dialectic: Plato's Demarcation of Philosophy from Sophistry', History of Philosophy Quarterly, Vol. 7, No. 1 (Jan., 1990), p.10.
Look at it this way. Plato later offered an infallible basis of knowledge in the Forms. Socrates did not claim knowledge; he was only an inquirer. A sophist could reply to Socrates that since he does not (even claim to) possess knowledge, his victories in argument were only that - victories in argument. Since he had no touchstone of knowledge or truth, he could achieve nothing more than victory in argument and this put him on no higher level than the sophists. He announced grander aims, crucially the discovery of truth and the acquisition of knowledge, but all he could deliver was nothing better than the sophists themselves, namely victory in argument.