Grazzt said:Yep. That's how I read it too. Auto hit. No roll needed.
Nope. The reason there's no "Attack vs Defense" line is because of this sentence right here:
PHB p. 288 said:You can deliver a coup de grace against a helpless enemy adjacent to you. Use any attack power you could normally use against the enemy, including a basic attack.
Coup de Grace is a rider applied to any other attack power. You still have to hit with that power, and if you do, you score a critical hit automatically.