The Austrian took control of the tournament with a remarkable run of five birdies in six holes to close out an outward 31, and he held his composure down the stretch following a one-hour delay due to the threat of lightning, maintaining his lead with eight straight pars.
Wiesberger wrapped up his third European Tour title in style, rolling in his sixth birdie putt of a flawless round from 25 feet at the 72nd hole to cap a best-of-the-day 65 for a winning score of 13 under par.??
As overnight-leader Jaco Van Zyl faltered, James Morrison emerged from the pack to claim outright second on 10 under after a bogey-free 67, making a late run at playing-partner Wiesberger with three birdies in five holes from the 12th.
The Open de Espana champion was unable to better par at the final two holes, but the runner-up finish guaranteed his place in the field for The 144th Open at St Andrews in a fortnight, while Van Zyl and Rafael Cabrera-Bello claimed the other two places on offer at the home of golf.
Van Zyl held a two-shot lead after 54 holes, but he made a nervy start to the final round with a bogey at the second and another at the eighth, and he parred every hole on the back nine to remain at eight under for the tournament.
Kaymer’s late slip
The South African banked the biggest cheque of his career for his third-place finish, one ahead of two-time major champion Martin Kaymer, who appeared primed to post his fourth sub-70 round of a vastly-improved week until he double-bogeyed the last after finding water.
Cabrera-Bello fired the most entertaining round of the day despite struggling to the turn in 40 after a double-bogey at the first and an ugly triple-bogey seven at the fifth before a birdie at nine revived his challenge.
The Spaniard holed his 123-yard approach to the 12th for an unlikely eagle-two, and he birdied the next before making another eagle at the par-five 14th to get back to go from one over to four under in just three holes.
Cabrera-Bello then made the first birdie of the final round at the 18th to complete an eventful 69 which proved good enough for outright fifth, one ahead of leading French player Michael Lorenzo-Vera.
England’s Andy Sullivan, Francesco Molinari and Brendan Steele, who triple-bogeyed 17 before closing with a birdie, joined Lorenzo-Vera on four under, but home favourite Victor Dubuisson laboured to a four-over 75 to finish 11 shots behind the champion on two under par.