Smith came to the crease early, following the cheap dismissals of David Warner (4) and Shane Watson (8).
Out of sorts and certainly out of luck, Watson fell in embarrassing fashion when he played onto his stumps.
The allrounder looked to have played a solid defensive stroke straight into the pitch, but looked on in horror as it spun back towards the stumps.
Watson haplessly swung a leg out to divert it from its path to the stumps - but his air swing was only able to cause uproarious laughter from the England team balcony.
His exit opened the door for a 112-run partnership between Smith and Glenn Maxwell (44).
Smith batted beautifully, and produced the shot of the day when he whipped a pull shot off his hip and into the top tier of the grandstand, but his dismissal proved fatal to Australia's cause.
Earlier, Australia's bowlers felt the wrath of a 135-run partnership between Moeen Ali and Eoin Morgan, which formed the backbone of the home side's total of 5-182.
Stoinis was smacked for six into the stands by Moeen with his first delivery - and his second raced along the ground for a boundary.
Combining with England stuttering at 2-18, Moeen (72 not out) and Morgan (74 off 39) countered brilliantly.
No bowler was safe from the onslaught as England raced from 100 to 150 in the space of 17 balls.
Young legspinner Boyce, brought on the tour purely for the T20 fixture, was handed the most severe punishment - conceding 19 runs from his six balls.
Morgan blasted Watson for two monster sixes which left the ground and landed near the neighbouring Taff River, where the ball was retrieved by a bemused bystander.
Cummins, bowling express pace, took two wickets in his opening over to rattle the home side.
The 22-year-old sent down some of the fastest deliveries of the tour, with the speed gun readings nudging past 150km/h - too quick for Alex Hales, who missed a full toss which cannoned into his stumps.
Morgan's superb innings was brought to an end when, chasing an eighth six, he was well caught on the boundary by Watson off Nathan Coulter-Nile.
- AAP