By pot roasting the joint, you are effectively cooking it in its own steam, which is why you end up with such a tender dish. If you would to add a large glass or two of red wine, or, even better, some Port, you can do no wrong !
It used to be my job to go to the butcher's every Saturday. The instruction was always the same: piece of brisket (no more than eight shillings). It would go into the oven first thing Sunday morning on a low gas, ready for lunchtime. I liked it but haven't had any for years.