Winningest?

Is "winningest" a real word? I heard it on the TV the other night, albeit American TV where English is a second language. I was staying at my cousin's place and her hubby, Darryl, was watching the Superbowl on Fox. It was the final few minutes of the match and Darryl was explaining a few of the rules (like why they wear those big macho shoulder pad thingeys). He has a knack of explaining sportipants stuff in an economical and non-yobbo fashion. He takes on the neutral tone of a learned outsider who might be explaining how a barbecue operates or some scientific law. Like he's not committed to the sport thing; it just is.

So the game ends and the Indianapolis Colts have won. It's pissing down raining and the suited hot-shots are standing out there getting drenched in their wools suits while handing out trophies. It must smell like wet dog out there. I'm not really paying attention until one of the commentators says something about them being the "winningest" team or their coach is the "winningest" coach.

I've never heard this word before. Is it a word? He said it like it was perfectly reasonable, but I wonder if it could be like the Springfield motto on The Simpsons:

A noble spirit embiggens the smallest man

in which the 'word' "embiggens" is a wacky Simpsonism.

Still, "winningest" is all over the internet and even has a dictionary entry on Merriam-Webster. So perhaps it's an Americanism or even a sportism (given that I magically tune out during the sport segment on the news and so might have missed the emergence of the term).

So I was grudgingly willing to accept the neologism until I encountered the following:

Who is the most winningest collegiate coach of all time?

That's got to be one of the depressingest things I've seen in the most longest time.