I like to think in terms of what has to happen for the Cards to win--
simply put -- they have to have to be no worse than even on the turnover margin
If they win, it will be in a low scoring game. In spite of the 41 point showing against the 49ers, I beleive KC's offense is pedestrian. They scored those 41 points with all of 300 yards of total offense, and benefited from 4 SF turnovers, at least 3 of which could be put in the "unforced" category. The Cardinals need to make KC go long fields, and when they do get into the redzone, settle for field goals.
A matchup I like for the Cardinals is Berry and Okeafor vs KC's tackles. They have to either get pressure on Huard and/or force KC to keep additional people in to protect.
That being said -- the Cardinal offense will be pedestrian as well. With Denny sick of the turnovers and a rookie making his first start, expect Leinart to run a very conservative offensive game plan with an emphasis on dinks, dunks and check downs.
If the Cards win, it will be a 16-13 kinda score.
Finally, I think the one advantage the Cards have is in the "desperation" factor -- playing at home, absolutley needing a win vs a KC team that thinks all is well after a post bye week drubbing of the 49ers. It has all the makings of a "trap" game for KC -- a road, non conference game early in the season coming off of a big win -- and with the KC Star reporting that their defensive players are thrilled to be facing Matt Leinart.