Brian Lara knows playing Australia in the final will be a huge challenge © Getty Images

Brian Lara is glad his side will have the chance to play the reigning World Cup winners in the Champions Trophy final on Sunday. But he acknowledged it would be a different challenge to when West Indies defeated Australia in their opening group match at Mumbai's Brabourne Stadium, which is also the venue for the final.

"Australia have gained some momentum since they lost to us," Lara told AFP. "They are very confident of their chances. We have to realise that we are going to play a completely different opposition to the one we played against.

"That time Australia were playing their first match and we had a sort of an advantage [having played three qualifying games]. It's a challenge but we will back ourselves." West Indies are gaining one-day momentum after beating India in a home series in May and reaching the final of the DLF Cup tri-series in Malaysia in September, which they lost to Australia.

"I won't say it's an unfinished business against Australia. I just feel it's nice to play them in the final again," Lara said. "Our one-day game has always been pretty good. It just required a little bit of fine-tuning. We did that in Malaysia. We were forced to play the qualifying round here and that in itself gave us a little bit of competitive cricket.

"It's nice to be playing the world champions in the final. It says a lot about our effort ... getting past South Africa, and beating India and Australia in group matches. So, we are looking forward to the challenge."