Injustice 2

There are a couple of ways to get this achievement. I am complete beat em up rookie and found myself getting this achievement quite easily with the right strategy.

First method: Boosting

You can start matches by using the gamer room and simply boosting this with a friend or fellow TA user. This is probably the fastest way, but depending on what you want from a beat em up game, there are of course ways to make this achievement pretty easy without boosting, too.

Second method: Finding the right oponent

If you don't feel like boosting this achievement I would strongly advise you to play some multiverse matches beforehand and to get used to a couple of fighters. Also leveling them up and unlocking some neat pieces of gear can't hurt either. When I started this I had a lvl. 20 Batman with some rare pieces and one epic piece equipped.
When you are familiar with a fighter or multiple fighters and have them boosted you can start searching for a suitable opponent.
As a rule of thumb I only picked people with a very low rank or with a higher losing ratio than winning ratio (Sure, this is pretty lame, but I knew me: I suck at these games!). Just keep declining the fighting offers till you find someone you think you could beat. Very often when you find yourself fighting against someone with a low level they won't have good pieces of equipment, which makes many of the fights very easy and puts the odds in your favor.

Whatever method you prefer, be aware of the fact that this achievement is actually pretty easy to get. As a plus you can work on your 200 matches achievement as well (in fact you could join every hard opponent as well and just quit out while being in the fighters selection screen. It still counts as a played matched. Nobody said something from winning 200 matches, right? :-D )

Hope this helps you guys!
Any improvements? Please let me know in the comments below!