How to get the hardest challenge: A grade-Attacking Scenarios Skill Challenge
After 2 hours getting max 18k points, I tried something else. Inspired by the daily FUT challenge of today I decided to score with Flair Shots (LT+B). With succes! Got it first try. You will score 1500+ goals.
Offcource I also changed my Rival and boosted Messi to 99 (see solution of xUniVerSeZz, thanks for that). Good luck!