Klein amassed a career-high 323 passing yards on 19-of-21 efficiency and ran for 41 yards as Kansas State (7-0, 4-0 Big 12) kept its unbeaten season intact.
The Wildcats rolled up 479 yards of offense to 243 for the Mountaineers, sparked by 194 yards and two TDs on nine catches from Tyler Lockett.
Kansas State racked up its fourth straight road win over a ranked opponent.
Early Heisman Trophy favorite Geno Smith was picked off twice, managing only 143 yards passing on 21-of-32 attempts for West Virginia (5-2, 2-2), which suffered its second straight blowout loss.
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