Chiefs beat both Super Bowl teams so they're basically Super Bowl champs— Arrowhead Pride (@ArrowheadPride) January 19, 2015
The Chiefs beat the Patriots way back in Week 4 on September 29. They destroyed them 41-14 on Monday Night Football at Arrowhead Stadium. A couple of months later in Week 11, the Chiefs beat the Seahawks, 24-20, at Arrowhead Stadium. That moved the Chiefs to 7-3 on the season (which is difficult to remember considering they didn't end up making the playoffs).
Those games prove that the Chiefs are capable of hanging with the NFL's best teams. It's just a matter of doing it consistently.
Also, if your first reaction to this is to get angry and / or clarify that the Chiefs are not actually Super Bowl champions, you are probably a real treat at parties.