The 21-year-old from Kirkhill overcame his fellow Glaswegian, Fraser McKenna, of Balmore, at the 22nd hole of a keenly fought tussle to set up a 36-hole showdown with Aubrey Barnard.
A fortnight ago, Fife's Brian Soutar kept the South African Open crown in Scottish hands. Now, Shields has the opportunity to make it a double as he tries to emulate David Law's Northern Amateur win of 2011. Add Richie Ramsay's success in the European Tour's South African Open at the end of 2009, and the pots of gold in this Rainbow Nation are taking on an increasingly tartan tinge.
Shields has plenty of matchplay pedigree but he has yet to make that step on to the winner's podium. He was runner-up in the Scottish Boys' Championship in both 2008 and 2009 while he was beaten to the South African Amateur title last year by Troon's Michael Stewart.
His determination to rid himself of that nearly man tag was in evidence yesterday with two battling victories. Shields fought back from two down with two to play in his quarter-final with Shaun Smith before winning at the 21st and then saw off the spirited challenge of McKenna at the fourth extra hole to seal a final berth.
McKenna, runner-up in the British Boys' Championship in 2008, had underlined his qualities with a one-hole win over South Africa's No 1, Brandon Stone, in the last eight but his glory bid was thwarted by Shields in the sudden-death shoot-out during the afternoon's semis.