When I saw the title, I honestly though this referred to the most humiliating victory... as in the victor being humiliated.
Back in S5, I was doing "just for the lulz" arena (my demo 'lock and his blood DK - you can already see how bad this will be). We were just screwing around, neither very well geared (I had the blue PvP crafted set; he had... just a trinket, I believe).
One of our matches, we run into a rogue. Not a rogue and anyone - literally a 1 vs 2 match.
Things looked grim for our heroes anyway, as the rogue survived my meta... then blew me up like I wasn't even there: ginsu blender time turning me into a pink mist. He turned on the DK and started shredding him something fierce, obviously about to win...
... then the rogue DCd, leaving the DK with less than 2k health. Victory for us! Well... humiliating... but victory nonetheless.