To unlock the Survival of the Fittest trophy in FIFA 19, you must win a Survival match.
To play a No Rules match:
- Go to Kick Off mode and choose a side with your controller > Advance
- House Rules > Survival
- Select the team and kits
If you're struggling to win the game, change the difficulty in Game Settings to a difficulty you can comfortably beat.
Win the match and the trophy will unlock.