A week or two ago I had a tough eye of round roast.
I put it in a casserole dish with about 1/2" of water, lay a slab of fat on top (trimmed from another roast, pork I think).
I then covered the casserole dish with foil and cooked it a couple more hours at 325. It came out so tender that I was able to shred the meat with just a fork.
Another DCer suggested a temperature of 275, but I had already done it at 325.
I had just happened to save the fat trimming, but I'm sure some fatty bacon would do nicely.
If you can't see the bright side of life, polish the dull side.