'We should win' - Marshall

A confident Xavier Marshall has tipped a world record and a West Indies victory after his career-high 85 kept the pressure on Australia entering the final day. Set 475 by Ricky Ponting, the hosts were 235 for 3 at stumps, with the safe hands of Shivnarine Chanderpaul guiding the chase following Marshall's dismissal.

"I think we should win this game," Marshall said after play. "Dwayne Bravo and Shiv, I think they can stick out there and bat out the day tomorrow."

Marshall's belief was matched by Beau Casson, who was excited by Australia's situation. "Anything can happen in cricket, but I certainly love being in our position," Casson told AAP. "A fifth day wicket is always going to be hard work, but we've got a lot of options, which is a fantastic position to be in. It's going to be a good test for us, but we're up to it."

Casson, who is playing his first Test, has figures of 1 for 58 and will be called on to make important contributions as the series concludes. He was pleased with his first breakthrough, which came with a topspinner to Marshall, and celebrated it hard.

"I looked at the replay and I did carry on a little bit," Casson told the ABC. "It's a bit of a monkey off the back, it makes you feel like you're contributing to the side. It was pure emotion, and such a fantastic catch [from Phil Jaques]."

Marshall left 15 short of his maiden first-class century when he glanced on to his hip and the ball popped to short-leg. It was more delicate than most of Marshall's strokes, which were highlighted by aggressive drives.

The serious ankle injury to Sewnarine Chattergoon, who is unlikely to bat, forced Marshall up to open and he caused some problems for the Australians during an innings that included 12 fours and a six. They also regretted giving him chances on 1 and 22 as he cut into the massive deficit.

"I was told by the coach [John Dyson] I'd open, so I kept my mind on that," he said. "Now I'm an opener, it doesn't matter to me. Anywhere they put me to bat I can bat."

Marshall, 22, first played for West Indies aged 18, but he has struggled to cope with the demands of international cricket and has even been dropped from the Jamaica side. While Chris Gayle and Ramnaresh Sarwan were two players who helped Marshall, he also received assistance from Pat Rousseau, the former West Indies Cricket Board president, in dealing with his off-field issues.

"[Rousseau] has been telling me good things, not only about cricket but everyday life as well," Marshall said on Cana News. The tips have worked and Marshall has collected two half-centuries in his past two Tests.

"I'm not surprised with myself," he said. "I've been working hard for the past few months. It is paying off now. I've been training harder, talking to guys who have been playing for a long time. I am doing things that are right, things that will get me through."