This is probably too late....I would drain it after 2 or 3 hours or so, pat it dry, sear it in some hot evoo on all sides in a deep pot. Remove from pot. Chop up some of the usual root veg. (onion, carrot, garlic plus some celery), brown these too in same pot. Toss the meat back in, add a half bottle (whole bottle if you like) of good red wine, sprinkle in some rosemary, thyme, ground black pepper, bring up to the boil, reduce to a simmer, cover tightly then leave it alone for 2 or 3 hours as time permits, but at least 2 hours.
In other words, pot roast :)
Turn it a few times and add extra water/beef stock if its looking dry. Once its tender, remove meat from pot, keep warm covered in low oven. Strain off juices and sieve veg to make your sauce, reduce it down or thicken with cornflour, whatever you prefer. Season to taste.
Slice meat, serve with nice seasonal fresh cooked veg, serve with sauce in jug.
Yum, my favourite way of cooking a lump of meat.
Or you could slice it after a few hours of marinading (could leave it to marinade overnight, will be even better) and grill/bbq/ fry. Nice with new potatoes seasoned and tossed in butter and snipped chives or chopped parsley and a mixed green salad.