If the DEF of the attacked Defense Position monster on your side of the field is higher than the ATK of the attacking monster on your opponent's side of the field, destroy the attacking monster. Damage calculation is applied normally.
Rulings
Individual Card FAQs
"Continuous Destruction Punch" is like "Destruction Punch" except it's a Continuous Spell Card that you activate during your Main Phase.
A monster destroyed because of "Continuous Destruction Punch" is destroyed by "Continuous Destruction Punch"'s effect, not "as a result of battle".
The determination of whether a monster is destroyed by "Continuous Destruction Punch"'s effect happens at Damage Calculation, so Flip Effects, etc., are resolved AFTER "Continuous Destruction Punch"'s effect destroys a monster (but does not yet send it to the Graveyard). Then, after applying Flip Effects, send a monster destroyed by this card (or by Damage Calculation) to the Graveyard.