Feb 20, 1982. Now i tried to research this, so it may not be accurate, but i believe it is. On that day, 18th ranked Ksu (7-4 in conf) played unranked KU and won in Lawrence. Kstate actually played KU later that year in the conf tourney and won as a ranked team too (And they also beat KU in 82' when we were ranked 18 and 3-0 in conf)
Almost 31 years in the making, but we are ahead of KU in the conf standings and surely will be ahead in the AP polls come Monday.