Best thing to do in the post for me has been bodying up and then using the right stick to contest, that way your man doesn't get out of rebounding position. Seems like the CPU usually is going to fadeaways too. They make a lot of tough ones, definitely, but you just have to live with that.
I got torched down the stretch by Zach Randolph last night. I was the Wizards, leading by 5-6 midway through the 4th and he just took over. I had Nene defending him well but it didn't matter. It was frustrating at the time but afterward I thought about it and thought it was kind of cool the CPU played their 4th quarter offense the way they did and Z-Bo just got hot.
After the CPU gets offensive rebounds, I recommend just bashing triangle at will lol, and with multiple defenders if possible. The CPU will still make a bunch but I'm starting to get them to miss some just going all out.