"upset"

[Laurence Horn]

This is an relevant etymology to inaugurate the March Madness season
(the NCAA college basketball tournaments).  The noun "upset" in the
standard political and sports-related senses, as in descriptions of
the New England Patriots' magnificent surprise victory in the Super
Bowl and glossed by AHD4 as 'a game or contest in which the favorite
is defeated', looks to be derived from the verb the way the other
nominal senses of the word are.  I've sometimes heard it claimed that
the actual origin of this nominal sense, however, is from the
unexpected victory of a dark horse (I don't know if he was a literal
dark horse as well as a figurative one) named Upset over Man O' War
in the 1919 Sanford Stakes at Saratoga--the only race out of 21 he
entered in which Man O' War was defeated.  This sounds like a folk
etymology to me, but I couldn't confirm this in the OED, which
surprisingly has NO relevant entry or cites in its (on-line) listings
for "upset".  Jesse, shouldn't this be rectified?  Whether or not
this sense of the nominal was around before 1919, it's certainly been
around for a while now.  (Sorry, I don't have other general
lexicographic resources that give first cites, and I'm not patient
enough to wait and see if the HDAS will ever get to U, assuming this
even counts as slang.)

larry