I also thought of an early one that will at least give a baseline:
At Vengeance 2001, Rock lost the WCW Championship to Jericho on the night where Jericho would later go on to defeat Austin for the WWF Title as well, to unify them as the Undisputed Championship (which technically is the WWF Championship)
Rock would then challenge Jericho for the Undisputed Championship at the next PPV, Royal Rumble 2002.
Kinda cheating since WCW/WHC aren't technically the same thing, but still.
--
Thank you, Eddie Guerrero.
http://www.wwe.com/f/styles/photo_large/public/photo/image/2012/04/33_Moscow_04112012jg_02128.jpg