Nathan Coulter-Nile's career-best 92 and Mitchell Starc's 5-46 earned Australia a hard-fought 15-run win over West Indies in an immense Trent Bridge tussle.
Coulter-Nile struck the highest score by a number eight in a World Cup and Steve Smith contributed 73 as Australia rallied from 38-4, then 79-5, to reach an unlikely 288 all out off 49 overs.
That target seemed well within West Indies' grasp for much of the chase as Shai Hope (68), Jason Holder (51) and Nicholas Pooran (40) all made solid contributions.
But in a tight finish, Starc dismissed Carlos Brathwaite and Holder within four balls - claiming his 150th ODI wicket in the process - before knocking over Shane Cottrell to earn his sixth five-wicket haul and inflict defeat on Windies on the occasion of their 800th recorded ODI.
It means that Australia have won 10 of the last 11 meetings between the teams, have been victorious in their last 10 ODIs and remain unbeaten in the early stages of this tournament.
Smith (73) and Coulter-Nile transformed Australia's innings after the top-order succumbed to West Indies' well-executed, short-ball plans.
Aaron Finch (six) did well to nick a crackerjack delivery from Oshane Thomas (2-63) before David Warner (three) carved Cottrell to backward point.
Usman Khawaja (13) seemed similarly unsettled after being struck on the helmet by Thomas and was caught on the drive by a flying Hope.
Australia's stumble continued when Glenn Maxwell top-edged a pull off Cottrell (2-56) but Marcus Stoinis (19) helped Smith rebuild in a stand of 41 before pulling tamely to mid-wicket.
Alex Carey (45 off 55) tilted the balance back towards Australia after overcoming a nervy start to take three boundaries off one Cottrell over and with Smith rotating the strike well, the total began to build.
Smith offered the rarest of chances on 26 when he top-edged a hook off Holder only for Cottrell to lose his footing at deep backward square when he seemed destined to take the chance.
Carey missed out on a fifty when he poked at Andre Russell but Smith, and then Coulter-Nile, wouldn't be denied - the latter celebrating reaching the landmark in 41 balls by striking the next delivery, a Brathwaite (3-67) full toss, down the park for six.
Coulter-Nile, whose previous best ODI score was 34, enjoyed a life on 61 when he was dropped in the deep by Shimron Hetmyer off Ashley Nurse, giving Smith the chance to bring up the 100-run stand in style with a four off Thomas.
Smith's march towards three figures was cut off in dramatic fashion, though, when he flicked Thomas to deep square where Cottrell took a stunning catch - plucking the ball out of the air one-handed before completing the dismissal after briefly stepping over the rope.
Coulter-Nile continued to plunder leg-side boundaries until, with a maiden century in sight, he holed out off Brathwaite - Australia's innings subsequently coming to a close off 49 overs.
West Indies lost Evin Lewis early in their chase but then enjoyed a major slice of luck when a delivery from Starc shaved Chris Gayle's off-stump without dislodging a bail. Two balls later Gayle successfully reviewed after being given out lbw to a Starc delivery drifting down leg.
The 39-year-old posted his 1,000th World Cup run with a driven four but was not to win a third review when given out lbw to Starc - the decision staying with umpire Chris Gaffaney's call.
West Indies remained ahead in the game as Pooran (40) - dropped by Maxwell on 31 off Adam Zampa - put on 68 with Hope before falling to a fine one-handed Finch catch at point.
Hetmyer picked up the baton in a 50-run stand with Hope only for the West Indies to lose another wicket when well-placed - Hetmyer stranded mid-pitch after being sent back by his partner to make it 149-4.
Hope had barely put a foot wrong until he chipped Cummins to mid-on and the burden on Holder grew a little heavier after Russell (15 off 11) fell to a fine catch by Maxwell, taking a hanging ball as he ran back from point.
Holder reached his ninth fifty in ODIs off as many balls and when Brathwaite (16) launched Coulter-Nile long into the midwicket stands, West Indies needed 46 runs off the last six overs.
The twists kept coming, though: Brathwaite undone by a Starc slower ball with Holder gloving a pull off the same bowler three balls later to put the match beyond West Indies' reach.
Watch Pakistan take on Sri Lanka in the 2019 ICC Cricket World Cup live on Sky Sports Cricket World Cup from 10am on Friday.