By Brian O'Driscoll Ireland star and BBC Sport Online columnist

It's hard to take in that I am to lead Ireland out against Australia on Saturday.

It was great to be named as one of the three vice-captains last week, but to take over from Keith Wood as captain is unbelievable.

There's hardly a bigger honour than to captain one's country and for me it's another challenge along the way.

I suppose they are looking forward to the future, and they are giving me a chance.

I heard the job was maybe in the pipeline when Keith got injured.

I've spoken to Fester at length, and he was very encouraging about the whole thing and had some words of advice to give to me.

But looking forward to the game coming up against Australia will be an opportunity for us to show how far we have progressed.

We have qualified for the World Cup, where we are grouped alongside the Wallabies.

Now we will see if we have moved on any since those two games against Georgia and Russia.

We have been training quite hard for a while now, and things have been going quite well.

I believe we have as good a chance as we have ever had to defeat Australia for the first time since 1979.

Australia, though, will be as tough as always.

They have had a few changes in their side lately, but they still have the core of their successful team travelling.

They continue to have huge potential to be magnificent on any particular day.

When you have players like George Gregan, Matt Burke, Daniel Herbert and Stephen Larkham, who have played a huge amount together, they are always going to be dangerous.

They are very intelligent footballers, and they possess a different strategy to New Zealand.

Whereas the All Blacks are a brilliantly-drilled side, Australia are a set of thinkers and can change the flow of the game at a whim with their off-the-cuff play.

I am now one of the more experienced players in the squad after making my debut three years ago, and I suppose it is the next step up the ladder.

'Tremendous potential'

I was a little disappointed that Leinster had to bow out of the Celtic League. As champions, it was doubly disappointing.

It was hard for the side to go into the campaign without 10 or 11 players who would have been in the starting line-up.

But we finished strongly, and it will enable us to concentrate fully on the Heineken Cup.

I believe the present format for the competition is fine. It encourages tries and it helps make the game attractive.

It still is a new competition, but once it does become good to watch it will encourage sponsorship and maybe more television.

I still think it needs a few years to take off, but it has tremendous potential, and I hope it continues to grow.

In the meantime, I'm focused on the next three weeks with Fiji and Argentina to follow Australia.