WWE 12

Select WWE UNIVERSE on the main menu and select the first RAW event open to you. Under MATCH CARDS, press A to select, then press RB to edit. You can either "Just Change the Participants" or "Customize Freely", then you are taken to the superstar select screen. Select your custom superstar (bottom left beside the random "?") against any opponent, and play the match. Win and the achievement unlocks.

*NOTE* I also unlocked Brock Lesnar as a playable superstar.