It is as much a fact of life as is night following day. Man Utd are one of the biggest clubs in the world. Occasionally it has been reasonable to say that they are the biggest, though not right now.
Even though they are losing some traction in Asia, ( they like to support the winners there) and their finances are an opaque mess of intractable debts, obligations and money seeping constantly out into the Glazers' pockets, still they are one of the biggest clubs in the world.
Anyone who has found themselves among ordinary people in other parts of the world, even pretty far out a few times in my case, will tell you the Man Utd is the name they ALL know. They are bigger than that lot, us and Boro put together, and no amount of wishing it wasn't so by these needy and inadequate characters is going to change that.
This doesn't bother us. It doesn't bother Boro. But it eats away at that lot's flesh and has been doing so since the nineties when after a couple of good seasons they thought, and often stated loudly, that "Man Utd are our rivals now". It was always an itch they couldn't scratch, now it has morphed into a scabrous flesh eating sore.