Rolls weathered a late comeback from Williams before getting across the line in style. He was 5-up with five to play but Williams won three on the trot.
Rolls calmly chipped in on the 17th for birdie-3 to seal victory.
The youngster showed steel in a 19th-hole quarterfinal defeat of Jeune, 42 years his senior and vying to become possibly the oldest winner of the PB Open.
Rolls, who played flawlessly for the first 12 holes, got into trouble on the first extra hole - the par-5 first. But he played a superb pitch shot in for four and calmly slotted a short but missable putt for par and the win after Jeune found the bunker for his third and was unable to up and down.
Today's other semi pitted top qualifier Mark Smith, of Rotorua's Springfield course, against Patutahi club champion Hukanui Brown.
Smith was untroubled in his path to the last four.
He beat Glenn Solomann - who plays at Whitford Park in Auckland but turned out for Waikohu in this year's Oligoi Jug men's interclub pennants - 5 and 4.
Smith then disposed of Poverty Bay's Reece Witters 6 and 5.
Brown knocked out 2007 PB Open champion Tony Akroyd (Electrinet Park) 4 and 3 and birdied the 18th to force a sudden-death playoff against seven-time PB Open champion Waka Donnelly (Napier).
Brown bombed his second shot on to the par-5 19th and a three-putt par was good enough for victory.
Van Der Nagel, like his Bay of Plenty masters representative teammate Smith, eased into the semis - knocking out Pete Stewart (Park) 4 and 3 and Dan Collier (Park) 7 and 5.
None of the four semifinalists have won the Open before, meaning there will be a new name on the Keiha Cup.
In other first-round matches yesterday, Witters beat Hamilton's Aaron Goddard on the 18th; Jeune won the last two holes, including a birdie on the last to edge 2021 Open champ and Park senior club champ Anaru Reedy; Donnelly defeated Glenn Morley (PB) 6 and 5; and Collier saw off Poverty Bay's Marcel Campbell 2-up.
Semifinals were held this morning and the finals of all seven divisions were in the afternoon.