You can actually hear Matthysse connect with the first Knockdown and the second one it seems unreal because of the speed and accuracy of it. Believe me it's really hard to see KO punches at times for this reason. It's also masked by the camera being behind Matthysse and him throwing the same left twice. Like an opponent you can look for twitches and give aways, but the fact you don't see it gives punchers like Matthysse that leeway to catch an often better all round boxer.