man marking has worked wonders for my defense... ever since I started man marking super teams like Real and Barca i've had much better time stopping them and containing their stars.
This is what I do, its similar to what I used to do in PES2010 which had fast players without the catchup bug, in 2011 you didn't need to man mark because of this flaw. I think this is why ppl find defending so hard this year beacuse of the defensive assist/catch up in 2011. Ok so I man mark with 2 players, you basically swarm and crowd the marked player making it hard for passes to get to him. Then ... your external defenders, if you can make them CBs and play them deep to prevent the side line running to cross scenarios. If you play too far up they will through pass you and get free, if you have them deep they can't do this, then its up to you to trap them with your 2nd defender and use R2 to keep them infront of you.