Though I agree that these days, he isn't trying that hard and does make a lot of mistakes. I think when he really wants to he can be good, and on most days he's good enough to get into rank 10 or so.
But the thing is its not really an 'achievement'; any reasonable deck can climb to those ranks. The real challenge is getting to rank 5 or so, and then to rank 1. At least for me :)