Zanotti posted a final round 65 to join Stenson (67), Frenchman Gregory Havret (66) and Spain's Rafa Cabrera-Bello (67) in the play-off in the 2 million euros event on the Gut Larcenhof course.
Current 305th world ranked Zanotti, competing in his 180th Tour event, matched the birdies of Stenson and Cabrera-Bello at the third extra hole, after Havret dropped out at the second extra hole, when rain began falling heavily, Sport24 reported.
Stenson and Cabrera-Bello were then in rough off the tee at the fourth extra hole, the par four 18th, with the Spaniard dropping out after finding water guarding the green with his second shot.
Stenson was reportedly forced to lay-up short of the green before then matching Zanotti's par.
However, Stenson then found the water with his tee shot at the fifth extra hole, the shortened par four 17th, with Zanotti laying-up with the aim of getting a par to win the tournament.
