Second Test, Adelaide, day four (close):
West Indies 451 & 284-8 v Australia 439
Gayle wore out the Aussie bowlers with a long and patient innings
Chris Gayle's 11th Test century, and first against Australia, kept the hosts at bay on an absorbing fourth day of the second Test in Adelaide.
Skipper Gayle ended unbeaten on 155 in a total of 284-8, batting with patience but quickly enough to create a lead of 296 and set up a fascinating final day.
On 12 at the start of the day's play in a total of 23-0, he built important partnerships throughout.
He hit 16 fours and one six and defied the Aussies for 271 deliveries in all.
The Test looks beautifully poised going into the final day and if West Indies can produce 10 wicket-taking deliveries on Tuesday they could secure their first Test win in Adelaide since 1993 - and their first anywhere in Australia since 1997.
Gayle's first partner of the day, Adrian Barath, had an eventful eight overs in the morning session.
The teenager survived an Australian referral decision for caught behind, smashed a cover-drive for four and was then unfortunately run out for 17.
Bowler Nathan Hauritz got his fingertips to a Gayle straight drive and when the stumps were broken Barath was short of his crease.
The Australians used their last unsuccessful referral on an appeal for caught behind against Gayle but needed no replay system to send Ramnaresh Sarwan on his way.
Sarwan got a touch on a short delivery from Mitchell Johnson and was caught by Brad Haddin down the leg side, ending a disappointing comeback for the Guyanese batsman - with scores of 28 and seven here.
At lunch West Indies were on 95-2 from 33 overs in all, with Gayle on 56 and the hugely experienced Shivnarine Chanderpaul on 12.
But Ricky Ponting brought on Doug Bollinger in the afternoon session and he gave his team new hope by dismissing Chanderpaul lbw for 27.
The left-hander held his ground momentarily but eventually walked without asking for a video review of the incident.
Brendan Nash joined his skipper in the middle and on seven survived a strong lbw appeal from Bollinger, who kicked the pitch in frustration when the decision failed to go his way. The Aussies could not refer the appeal.
Gayle, batting with great sense given that none of his team-mates were able to really establish themselves at the crease, defended cautiously in the main before whipping the odd boundary through the on-side when given the chance.
He reached his century by sweeping Hauritz - beginning his celebrations before completing the third run - and at tea the Windies led by 195.
I think it's enough runs, that's my personal view. We know for a fact that the Australians don't like to be under pressure
David Williams, Windies coach
But they lost Nash six overs into the final session, the batsman comprehensively yorked by Shane Watson, and - after Dwayne Bravo had added a further 57 with Gayle - three deliveries from Johnson changed the complexion of the match.
Bravo drove a wide ball to gully and Denesh Ramdin was bowled by a straight one, and the response by Gayle and new partner Darren Sammy was to attack.
But Bollinger got enough reverse swing to force Sammy to edge to slip, and with five balls left in the day Sulieman Benn top-edged a pull to mid-on to give Johnson his fourth wicket of the day and seventh of the match.
Although the draw is perhaps the likeliest result, only two of the last 17 Tests at Adelaide have ended that way and either team may force a winning position on Tuesday.
But Australia, 1-0 up in the series with only the Perth finale to follow, can opt to bat conservatively when Gayle declares - or when his team are finally bowled out.
West Indies' interim coach David Williams said: "We're going to probably sit tonight and come up with a decision whether we feel we need more runs or if we're just going to call it quits and bowl from the start tomorrow.
"I think it's enough runs, that's my personal view. We know for a fact that the Australians don't like to be under pressure. It's a pressure sport."