2k11 question, how to improve defense?

I'm playing as an SG. I suck at defending my matchup in 2k11, they end up scoring nearly 90% of the time, which really hits on my SP bonus and grade. I just find it really hard to defend him on and off-ball, because off-ball, I try and intercept any pass from the PG, which leaves my man clear to shoot, and on-ball, he always pump fakes which makes me jump to block, he runs around and scores.. how can I improve?