If defeating a public claim would greatly benefit its opponents, and they possess the relevant skill and opportunity, the absence of a credible preserved counterexample becomes a significant historical consideration.
Motives for transmission and availability of means strengthen that inference: a genuinely decisive reply would be likely to attract attention and circulation.
Still, the mere absence of a report does not prove that every conceivable event was impossible. The argument depends on the full historical context of the challenge, opposition, competence and expected publicity.