Senior birdied the final hole of regulation to force the playoff. Both Pavin and Senior closed with one-under 71s to end at 11-under-par 205.
They returned to the par-five 18th. Pavin got up and down for a birdie, while Senior only managed a par.
The victory for Pavin was his first on the Champions Tour.
Mark Calcavecchia had six birdies in a nine-hole span from the third at The Old Course at Broken Sound Club. However, he bogeyed six of the last seven holes to tumble into a tie for seventh at minus-eight.
MORE TO FOLLOW.