Phantom Breaker

Okay, i wish i could you a much better solution here, but i do my best to help you guys out.

First things first: Change the time to Infinity in the game settings. Now go to arcade mode and press start with your second controller to bring in another player. Pick Infinity for your main character (hard style) and Cocoa (style doesn't matter, but i also picked hard) as your second player. I pressed X with both characters to start counter attacks to fill up the burst gauge to 200%. You only need Infinitys burst gauge at 200%.

Now press with Infinity to start your Overdrive and attack with Cocoa. I was using forward + , but i rarely blocked the attack with Infinity. After many attempts without success i switched over to a simple button attack and after a couple of hits the achievement unlocked.