Australia won the toss and put Scotland in to bat, looking to test Oli Hairs – who was back in to replace Michael Jones – and George Munsey early on.
The Scottish openers faired slightly better than on Friday – Munsey scoring 25 – but again it was McMullen who anchored the Scotland attack with a brilliant 56 at number three.
He looked like adding a few more but was dismissed by an incredible one-handed catch from Travis Head.
Michael Leask and Mark Watt provided some support to McMullen in the middle order, but Scotland’s tail collapsed quickly and they were only able to reach 149-9.
Australia’s target was set, but they would not reach it as quickly as they did in the first game.
Jake Fraser-McGurk has not enjoyed the best time in Scotland and he was dismissed for another duck off a superb diving McMullen catch.
Head was out in Currie’s next over after spooning one in the air that was caught by Munsey and some optimism crept around the ground after three overs.
Mitchell Marsh and Cameron Green looked a little nervous in the middle, edging balls around the field, but they managed to survive until the ninth over for a solid partnership of 61.
The big hits started coming and Scotland could not stop the flow of runs, with Green adding four sixes in his half-ton en route to victory as the sun started to shine on the Grange again.
