Board Thread:Naruto Discussions/@comment-3568954-20160805100852/@comment-25218206-20160807122849

Minato 87 wrote: Sasuke had time to move before Zaku activated the attack (at the moment when Zaku was screaming Supersonic Slicing Wave, we didn't see what Sasuke did. That's the reason why Dosu compared Sasuke's speed with a blink of an eye not with a sound).https://youtu.be/sW4pVcO-IVs?t=346

Anime isn't canon. In the Manga Zaku fires his supersonic blast and by the time it reaches Sasuke, Sasuke has already traveled like a dozen meters and is right behind Zaku. Sasuke moved a dozens meters+ in the time it took a mach 2 blase to reach him. He clearly outsped it.