WWE 2K18

Here's the most easiest way to earn it.

First go in the main menu choose play.
Choose one on one.
Choose normal.
When it shows character selection press Y to bring up match options.
Choose custom match rules.
Where it says pin and submission turn that off.
Scroll down to where it says Finisher Match turn that On.
Click accept.
Next one is rules, you can skip that so just choose accept.
Now on the environment options. There's a finishers (match start) option. You want to have that set to 1.
Now that you done that you can press X to save those settings.
It'll have a screen pop up asking to name it just type whatever you want, I put easy wins. Then click accept.
Choose whichever arena, ref, momentum and entrance you want then click accept.

Now choose your character you want to use and an easy character to face.
Start match.
Now run towards your opponent using LT hit X near opponent.
When opponent is laying down press Y for a charged finisher.
You'll hit the finisher then bam done. About 10 seconds.

I'll recommend doing this for all the superstar related achievements.

There is a very easy way to get this. First I turned on "squash match" in the options and maxed it out. Then I created a CAW with all his stats turned down, giving him an overall of 0. (I named him Fragile Fred.)

Next, I used a high overall character. I personally chose Goldberg, but any high level character should work fine. Honestly, pretty much any character will probably work, I just chose a high level one to be safe. I selected my high level wrestler, paired him against Fragile Fred. You will get your finisher in only 2 or 3 moves. Simply nail him with you finisher and pin. Achievement unlocked! I made the video below to show you exactly what i did.

If you would like to save yourself a few minutes of work, and give me a few downloads, I've uploaded Fragile Fred to the community creations. Please feel free to download him, I'd appreciate it!