Take your foot off the gass.I really really need help defending... I just find it so hard to contain any team. HELP!! any tips?
Dont put too much pressure.
Focus more on what can they do next rather than what they are doing.
Switch players and shadow their strikers.
Use jockey. A lot.
Sliding tackles only when you are 100% sure they are locked in a run and you will be able to reach them.
Dont panic.
These work for me.
Oh yeah - like @Anth James said - dont even bother with contain button. Useless.

some sliding tackles look off in certain situations but i'm happy that EA was actually doing "something" reg. the fouls. needs to be seen over a period of more matches.
...and i put that down to the latest patch. does the AI have more low shots on taget now?
so, its just in my head!