After Kansas City went three-and-out on the first overtime possession, Jason Campbell connected with Jacoby Ford on a 47-yard diving catch, and one play later Janikowski split the uprights for the win.
Campbell finished the day 19-for-33 passing for 229 yards, one touchdown and one interception. Ford had six catches for 148 yards and returned the second-half kickoff 94 yards for a score for the Raiders (5-4).
The Chiefs (5-3) were led by Matt Cassel, who went 20-for-35 passing for 216 yards, two scores and an interception.
Dwayne Bowe and Verran Tucker were on the receiving end of touchdown passes for Kansas City.