For this trophy, you must watch a replay with a friend. In order to do this, you must go to the multiplayer and from there select replays. At the bottom you'll see "watch with friends" and after clicking this a lobby will be created. Once you've created the lobby, invite a friend by pressing square. Once they've joined, press X and select a replay from your saved replays, once you do press O to exit the screen and you'll ready up. Once the other person does the same you can watch the video from there and the trophy should be yours!
If you don't have a saved replay , simply play a match of multiplayer be it local, player or even ranked to it's finish and press X through the challenge progression screen. You'll then have a list of options, press "save replay" and then refer to the first portion of this solution.