The way BB explained will work as a basic solution, but remember that Beat em Up games are different from fighting games - you will have more than one enemy on the screen and they can break your move.
So you either:
a - use a follow animation without any bbox on your player (this will prevent you get hit)
b- use a custom pain animation
c - use script and bind the enemy to you.
While the first option is easier, there is one downside: the other player can interrupt your move if they hit the enemy. The second option also works, but you will need to make a custom pain animation for all the enemies and it you got a TIME OVER, the enemy will continue executing the custom animation and it will be weird.
I had this issue on my Avengers game when I was coding Iron Fist. Then I changed to a scripted grab and now it works perfectlly.