Australia have arrived as a force at the World Twenty20, just in time to wave goodbye to Pakistan, as they completed a 21-run win in Mohali. A storming display with the bat was followed by an improved showing with the ball, setting up what will be effectively an elimination match against India in the final match of the Super 10s on Sunday.

The captain Steven Smith chose Mohali as the venue where he found his rhythm, in turn modulated then audacious in an innings that controlled the tempo of a strong total. He was helped in large part by Shane Watson, who batted with the air of a man freed of tension by his retirement announcement on match eve. Together, their stand left Pakistan with a total too steep despite friendly batting conditions.

In the field, Adam Zampa again bowled with considerable intelligence and character for Australia, winning a duel with Shahid Afridi that Pakistan's captain could not afford to lose if he wished to stay in contention for the semi-finals. James Faulkner's over-the-wrist slower balls then cut a swathe through the latter part of the innings as the run rate climbed, leaving him in possession of Australia's best T20 bowling figures.

Pakistan's chase began firmly, as Sharjeel Khan, Khalid Latif and Umar Akmal all played with considerable flair. Nathan Coulter-Nile was subjected to some particularly harsh treatment, and at 85 for 2 in the 11th over the match was overmuch open to Afridi's men.

However, Zampa showed his nerve by finding a way past Akmal, and two overs later followed up by coaxing Afridi down the wicket. The stumping was completed without fuss by Peter Nevill, who has provided a steadying presence behind the stumps in this tournament even though he is not in the batsman-wicketkeeper mode that has become dominant in the 21st century.

From there the required rate climbed with increasing steepness, too much even for Shoaib Malik, who hit out firmly at the end. Australia's lack of a second spin bowler to support Zampa has been a point of some contention, but Faulkner's past as a left-arm wrist spinner has helped him assemble a strong array of change-ups that flummoxed the lower order. Josh Hazlewood and Glenn Maxwell also contributed tidy overs to the cause.

Smith had named another reshuffled Australian side with the soon to retire Watson dropping down the order to make room for the return of Aaron Finch at the expense of Mitchell Marsh, while Hazlewood was included ahead of John Hastings. Pakistan recalled the fit-again Wahab Riaz in place of Mohammad Irfan, who was described as resting by his captain Afridi.

On an excellent pitch offering some sort of help for batsmen and bowlers alike, Mohammad Amir fought a fascinating early duel with Usman Khawaja. Amir's pace and movement unsettled Khawaja in ways seldom seen over the past few months, and while the opener scored swiftly, it was without his customary assurance. When Wahab replaced Mohammad Sami at the other end, Khawaja remained fretful, and was yorked giving himself room - Amir had undoubtedly played a part.

Finch and David Warner did not linger, but Maxwell produced one of the strokes of the tournament with a pure off-driven six that left many wondering why he seems compelled to resort to the outlandish so often. Even so, there was still much work to do when Smith was joined by Watson, on a ground where in 2010 he made one of his two Test hundreds.

Smith's concentration had been fierce, with Warner and Maxwell's blows allowing him to hustle into an innings without trying anything too lateral. Watson's arrival had Smith taking his tempo up several notches, as they charted a course to a total near 200. Initially, Watson looked a little unused to the middle order, but after scrambling to 10 from 10 balls, he detonated.

Watson's sheer power was shown when he muscled Amir over long-on and underlined once more with a glorious six inside out over cover from Sami. Meanwhile Wahab's efforts to stop Smith from levering the ball through the leg side reached a memorable extreme when Australia's captain took guard well outside off stump. Wahab followed him wider, yet Smith was still able to flip a boundary over midwicket that will make all the tournament highlight reels.

In all, Watson and Smith added 74 in 38 balls. Amir and Sami conceded 92 between them without taking a wicket, figures that appeared unlikely when Khawaja had been groping unsuccessfully at the left-armer's new-ball swing. Australia grew in strength from there, much as they have in this tournament. The meeting with India looms large.