Since the latest update/patch, this achievement has become considerably easier to obtain! You no long have to win 5 consecutive games! The streak box is now gone and has been replaced by a Crimson Omen box.
Instead of 5 wins, you now need 10 omen coins. Every tower or leader you take down in a versus match will provide you with 1 crimson omen coin.
So, for example:
If you take down both turrets and the leader, you get 3 omen coins at the end of a match.
Take down the two turrets, and you get 2 omen coins.
Once you have filled the omen box with 10, you just have to open it up and the achievement is yours! Theoretically, this could take as little as 4 matches.
If I have missed anything or you have any questions, please let me know!
Update from GymBeanNZ:
"Also, something to note: The achievement popped during Horde mode for me."