Australia 307 for 2 (Marsh 177*, Smith 63*, Warner 51) beat Bangladesh 306 for 8 (Hridoy 74, Shanto 45, Zampa 2-32, Abbott 2-61) by eight wickets
Australia's aversion to chasing has disappeared ahead of a semi-final with old foes South Africa after a statement innings of 177 not out from Mitchell Marsh at No.3 helped his side cruise to their second-successive record World Cup chase against Bangladesh in Pune, running down 307 with eight wickets and 32 balls to spare.
Marsh made his highest ODI score and his first century at first drop, thumping 177 off 132 balls with 17 fours and nine sixes in brutal fashion.
Australia had only chased more than 300 once in the last four years, but the rejigged batting line-up finally clicked with Steven Smith making an untroubled, unbeaten 63 at No.4 and sharing in a 175-run stand to guide Australia to their seventh straight win of the tournament.
They made mincemeat of a toothless Bangladesh bowling attack that had fewer runs to defend than they should have after their batters butchered an outstanding platform to post just 306 for 8 on a pristine Pune batting strip.
Towhid Hridoy had earlier made his highest World Cup score of 74, but six other Bangladesh batters passed 20 with none of them making more than 45. Adam Zampa again put on a masterclass of middle overs bowling to take his World Cup wicket tally to 22, the second most of any spinner in tournament history, while Marnus Labuschagne produced two outstanding run outs to continue to prove his worth to Australia's team.
Bangladesh's only solace will come from the fact they avoided damage to their net run-rate and will likely qualify for the Champions Trophy barring the Netherlands upsetting India.
Marsh's second century of this World Cup was easily his most important. As good as his innings was when opening against Pakistan earlier in the tournament, his significantly inferior numbers at No.3 had left some questions about the balance of Australia's top seven.
But the fall of Travis Head in the third over of the chase allowed Marsh seven overs of powerplay batting to get comfortable again, and he made the most of it. His ball striking was as imposing as ever, standing tall and holding his shape to thump drive after drive on the up through the cover region. Having been tied down by spin at different stages during the tournament, he showed no such fears against Bangladesh. Long-off and long-off fielders were merely spectators as he mishit balls 20 rows over their heads. He scarcely made a mistake. He barely played and missed. His only worry was having cramps late in the innings. But he powered through and kept his tempo up as he and Smith never gave Bangladesh a chance to open the door to Australia's middle-order.
Marsh formed another outstanding partnership with David Warner who made another composed contribution. Warner made 53 off 61 in a 120-run stand from just 17.2 overs and looked completely untroubled until he inexplicably chipped Mustafizur Rahman to mid-off. It could have been a moment of controversy as Bangladesh's acting captain Najmul Hossain Shanto took the catch easily before losing control of the ball when he clipped his own leg as he went to throw it in the air. But Warner walked off without a qualm, bitterly disappointed at throwing away a possible third century in this World Cup.
It brought Smith in at No.4, a position he has been shunted to begrudgingly to accommodate Head and Marsh above him. But any fears Australia's hierarchy may have had about the Marsh-Smith No.3-4 dynamic were quickly erased as he found his trademark rhythm and flow at a venue he loves. Having played for the Pune franchise for three seasons in the IPL and scored a Test century here, he looked right at home as he turned the strike over consistently and found the boundary when he needed to. He even added some inventive lap sweeps to relieve pressure and backed himself to clear the rope when he was beaten in flight.
It leaves Australia's selectors with a quandary when Glenn Maxwell returns for the semi-final having been rested in this game following his cramp-riddled 201 not out against Afghanistan just four days earlier.
That apart, Labuschagne's contributions in the field were phenomenal to ensure Australia weren't chasing more than 306. His two outstanding run outs stalled Bangladesh's march as Australia's bowlers lacked penetration. Mitchell Starc was rested and Josh Hazlewood only bowled seven overs, for just 21 runs, to keep him fresh for the semi-final.
Australia's other four seamers, Pat Cummins, Sean Abbott, Marcus Stoinis and Marsh bowled 33 overs for 210 runs and only picked up three wickets.
Bangladesh's top order, led initially by Litton Das, Tanzid Hasan and Shanto dominated the seamers with some sublime timing and brave footwork. Tanzid and Shanto skipped down the track and flat-batted length balls down the ground. Litton pierced gaps with pure class. But they all butchered starts. The worst of which was Shanto who looked set on 45 when he took on Labuschagne for two and was run out by a mile.
Hridoy, who played impressively to make his first World Cup half-century, then called for a suicide single to Labuschagne at cover. He swooped like one of his childhood heroes Jonty Rhodes, diving, gathering and underarming in one motion to hit direct from close range and run out a helpless Mahmudullah just as he was starting to roll on 32.
Zampa was able to take control through the middle overs. He had already forced Litton to hole out needlessly to long-on for 36 after scoring just five singles from the first eight balls he faced off the legspinner. Zampa later tied Mushfiqur Rahim in knots before forcing a miscue to midwicket.
Sean Abbott, who had replaced Starc for his first appearance of the World Cup, then bowled superbly at the death delivering slower ball bouncers with precision to concede just four runs off the bat in overs 48 and 50 and finish with figures of 2 for 61 from 10.
Australia's only concern with the ball was Marsh and Stoinis' contribution of 1 for 91 from nine overs between them. But Marsh's magnificent century more than made up for it, and Maxwell's return means their overs may not be required in the knock-out games.