Is "winningest" a real word?

I still cringe when I hear news presenters use the word "winningest". Maybe I shouldn't; maybe it's just the Englishman in me (it's not a word that would be considered acceptable outside of North America).

It's pretty much only used in a sports context, but it still sounds kind of uneducated to me, even if it is widely used on major TV and radio networks. At the very least it sounds very informal, and probably not appropriate for the 7 o'clock news, in my humble opinion.

That said, it's also a pretty useful word, and a neater solution than "player with the most wins", for example. Just don't try using "winninger" - not a word.

And don't get me started on "funner"...