West Indies 283 & 192 for 3 (Brathwaite 101*, Mayers 0*) need 306 more runs to beat Australia 598 for 4 dec & 182 for 2 dec (Labuschagne 104*)
Captain Kraigg Brathwaite scored his 11th Test century to defy an Australian attack without Pat Cummins as a gutsy West Indies pushed the first Test into a fifth day.
Needing a record 498 runs for victory or - more realistically - to bat through 154 overs to draw, Brathwaite superbly batted through the final two sessions of day four to provide hope for the injury-hit tourists.
But West Indies' chances of starving off defeat in the series opener still appear unlikely even amid the uncertainty over Cummins, who did not bowl after experiencing quadricep soreness/ He returned to the field in the final session and appeared to be moving around without obvious discomfort. An assessment tomorrow morning will determine whether Cummins can bowl on the fifth day.
Nathan Lyon relished shouldering more of the workload and claimed two wickets as he conjured menacing bounce on the Optus Stadium surface.
Leading from the front, Brathwaite was in sublime touch and scored uncharacteristically quickly to make Australia's shorthanded attack toil. He reached a deserved ton just before stumps but will likely need to bat for the long haul on day five to thwart Australia's bid for victory.
Brathwaite passed 5000 Test runs with a gorgeous drive down the ground to capitalise on the unavailability of Cummins, who had starred in West Indies' first innings to claim his 200th Test wicket.
Former skipper Steve Smith took the captaincy reins during Cummins's absence as Australia failed to make inroads against Brathwaite and debutant Tagenarine Chanderpaul, who batted mostly untroubled through the entire second session. Chanderpaul scored just three runs off his first 36 balls in an effective rearguard alongside a fluent Brathwaite.
For a spark, Smith even resorted to Marnus Labuschagne who bowled medium pacers instead of his usual legspin but it didn't do the trick.
But the return of Cummins, even though he couldn't bowl, was surely a tonic for Australia as quick Mitchell Starc finally provided the breakthrough when Chanderpaul chopped on to end an impressive Test debut with scores of 51 and 45.
Starc made amends after dropping Chanderpaul moments earlier on the boundary with Australia's frustration underlined by Cameron Green punching the ground having missed out on a wicket.
Australia's mood brightened when Lyon picked up Shamarh Brooks, who as the concussion substitute had batted well against the odds in the first innings but fell cheaply second time around after edging to slip.
Australia hoped to tear through West Indies amid the ground's increasing shadows but Jermaine Blackwood successfully reviewed a lbw decision off Josh Hazlewood. However, He never looked comfortable and fell to Lyon just before stumps.
Australia had earlier declared their second innings at lunch after Labuschagne added a ton to his first innings double century. Labuschagne rode some luck to become just the third Australia batter after Greg Chappell and Doug Walters to score a double century and century in the same Test.
Labuschagne made 308 runs for the match to continue a personal run spree at Optus Stadium after he scored 143 and 50 against New Zealand three years ago in the last Test played at the ground.
Labuschagne received luck on his way to his ninth Test century when he top-edged to gully via his helmet but was reprieved by a no-ball from Alzarri Joseph amid a riveting battle.
After receiving medical attention, Labuschagne continued on his merry way and passed 2000 Test runs in Australia in his 31st innings. Only Sir Don Bradman (19 in England and 26 in Australia), and Sir Garfield Sobers (29 in West Indies) have achieved the milestone in a country faster.
David Warner, however, missed a golden opportunity to end a three-year Test drought when he fell for 48, while Green didn't bat in the match in his debut Test at home.
West Indies' shorthanded attack was unable to limit Australia with spearhead Kemar Roach forced off after injuring his left thigh, while seamer Kyle Mayers did not bowl in the innings due to a strain in his right teres major muscle.
Adding to their woes, top-order batter Nkrumah Bonner was on day three substituted out of the match with concussion after being hit in the back of the helmet from a Green short delivery.
But the beleaguered tourists reached the final day and their hopes rested on their gritty skipper.
