Iowa State (2-2), which lost its 13th straight road game, scored first in overtime on a 37-yard field by Grant Mahoney for the Cyclones' first lead.The Rebels needed one play to win it.
Clayton, who finished with three touchdown passes and one touchdown run, threw a perfect fad pass to Payne in the corner of the end zone. The same play helped the Rebels force overtime last week in their 23-20 upset of Arizona State.
UNLV (3-1) surrendered a 21-point second-half lead as Iowa State quarterback Austen Arnaud accounted for four touchdowns. The last was a 28-yard scoring strike to R.J. Sumrall with 3 seconds to play to force overtime.
The victory was UNLV's third of the season, which surpasses its win total of two in each of the past four seasons.