This achievement, whilst annoying isn't hard. Just annoying.
To meet the criteria, you need to achieve a GREAT (to be safe) victory with a rage art being your final move.
So first off, to achieve a Great victory you must win the match when you are on low health. It looks like you have around 2-3% left. Flashing red isn't enough, you literally have to have a slither left. If it says KO your health wasn't low enough chances are, although there is a small window that's let's KO count.
So the strategy -
I did this in Offline Arcade Battle on easy using Miguel as he has an easy rage art. Other easy examples are Katarina.
Beat the opponent down until they are at low health (5-10%). Then let them beat you down until you are at low health, around 1-3%. (flashing red or being in rage isn't enough).
Then use your rage art as the last move. For example, Miguel's Rage art is :
. Katarinas rage art is
Repeat this five times to pop the achievement. This will take a few goes as quite often you won't get your health low enough to achieve a great rating.