But there is a better way, and it works with almost any bottle.

Take bottle firmly in one hand, angled slightly away from your body, and with a powerful, but controlled motion, run the back of your sword up the bottle to catch it just under the closure. It will work with anything with a lip on the bottle, ie beer etc, most wine and champagne
bottles.

like so:
http://www.maisons-champagne.com/encyclopedie/vignes_au_plaisir/images/canardduch_sabre.jpg

Of course, you can achive the same with a shrp corner, or many other tools, but that's not the point.