Pakistan went into bat first, and Misbah-ul-Haq top-scored with 34 runs off 54 balls as Australia dominated from the field.
The hosts suffered another wobble six overs later when Wahab Riaz claimed the wicket of big-hitter David Warner, who guided the ball in the air to third-man, where Rahat Ali was placed to take the catch.
With Warner heading back to the pavilion having hit 24 off 23 balls, the responsibility fell onto the shoulders of captain Michael Clarke, but he managed just eight runs as Riaz claimed his second big wicket of the innings.
The momentum swung in Pakistan's direction, but it didn't last long as Steven Smith boosted Australia's attack by racking up the run-rate and getting boundaries on the board.
Smith put his side in control, but he was eventually taken out by Ehsan Adli after hitting 65 runs, including seven boundaries, off 69 balls.
Australia will face India in the semi-finals.