This was the third triples title in a row for the Scots, with Peacock skipping the team in 2004 at Ayr and again in Christchurch four years ago.
An emotional Peacock said: "Winning this title once was brilliant, twice was just a dream but to retain it and beat the Aussies on their home patch is simply awesome."
The home team of Wayne Ruediger, Brett Wilkie and Mark Casey only scored in five of the match's 15 ends, but the Scots just edged the verdict 13-12.
Early on the Scots lay count after count, only for Casey to cut then down consistently. His hard work paid off when the Australians scored six shots in the ninth end to square the match 8-8 and, two ends later, they added a treble to take an 11-10 lead.
The match burst into life at that stage but a staunch following urged the Scots home, counting singles over the next three ends, with Archer raising the roof when he smashed the jack clean through to the ditch to take a second shot which was enough to secure the title.