Winning a Ranked match wont come easy. It takes knowledge of your character and knowledge against your opponent. The more you play the easier wins will come because you will learn the tendencies of online players. People are creatures of habit and you will notice that people repeat the same things over and over again online.
You only need to win once to earn this achievement.
For Glacius the best things to learn quickly are the range of your Shatter (it is unblockable) and the timing of your Puddle Punch. Those both go a long way to getting a win.