Chris Gayle has called for the West Indies to show belief and fight back in the best-of-five one-day series in Australia.

Predicting a 4-1 series win to the Windies before the series began - a prophecy now haunting him at every press conference - Gayle wants his team to at least go down swinging in tomorrow's limited-overs clash at the SCG.

While he has not given up hope of a massive turnaround and unlikely series victory, the Windies skipper will settle for a competitive performance after heavy losses in Melbourne and Adelaide.

Asked what he told his players in a huddle during a training session at the SCG, Gayle replied: "Just to remind the guys to still have the self-belief, still have that self-confidence to go out there and beat Australia.

"We have to keep reminding each other how good we are and that we have the capability to get the job done."

Gayle accepts the enormity of the task confronting his team with Australia dominating in every facet of the game over the past two matches.

"They definitely execute better than us. They are more disciplined than us as well," Gayle conceded.

"The majority of the time we set targets and we don't actually live up to the expectations.

"We need to try to execute and be a bit more disciplined in all areas.

"They (Australia) are one of the best teams in the world.

"Once they gain that sort of momentum, it makes it even harder.

"But we're up for it and we're looking forward to it."

Gayle confirmed the West Indies will make changes to their line-up for Sydney but would not divulge further details publicly.

"It's a very important game for us. We're 2-0 down so this is a must-win for us," he said.

"There are no two ways about it - we have to get our act together and try and step up to the plate."

Australia have also made changes, resting Shane Watson and Brad Haddin with James Hopes and Tim Paine drafted in.

Despite cruising to consecutive wins over the tourists, Australia coach Tim Nielsen insisted his team would not be lacking in intensity or motivation as they look to finish the summer without a loss for the first time in a decade.

"We have the opportunity to go through an Australian summer undefeated, which is something pretty special and for a youngish, newish group, it would be a real feather in their cap," he said.