Yugioh question plz help!?

Ok so I was dueling this dude and i had Super Conductor Tyranno ATK/3300 and the kid had a time wizard which we all know is pretty weak and a costly effect anyways whats weird he attacks me with that time wizard and because my monster of course a lot higher then his, he activated "Sakuretsu Armor" which its effect is "you can only activate this card when your opponent declares an attack. destroy the attacking monster" now seeing how his monster is a lot lower then mine technically his was destroyed by battle so would sakuretsu armor work!?!?!?