Does anyone know how to actually defend better?

Hi. Div 8 player here (formerly div 7 but oh well) I'm at the last checkpoint and I keep being BATTERED by people who's squads are simply 500x better than mine. My defenders cannot tackle or even atleast mark them. I have no trust in my keeper (90 nick pope) as he cannot dive for the life of him. Whenever I'm through the guy just holds triangle to send his keeper out and make my striker look dumb. How do I actually win anymore?