Brian O'Driscoll may have missed out on the Lions captaincy but Ireland's genius centre still provides the squad's main source of stardust.

With Gavin Henson and Jonny Wilkinson injured and Shane Williams worryingly out of form, the Lions are light on genuine game-breakers.

The responsibility of piercing South Africa's defence, the most aggressive in the world, falls squarely on the shoulders of O'Driscoll.

Being relieved of the leadership duties he fulfilled in New Zealand four years ago may have come as a bitter disappointment, but it could yet prove a masterstroke by head coach Ian McGeechan.

Free to focus on what he does best as Ireland team-mate Paul O'Connell takes the burden of captaincy, O'Driscoll can train his sights on spearheading the assault on the Springboks.

"I'm looking forward to concentrating on playing and trying to stay relaxed," said the 30-year-old.

"I'll focus on playing well while helping the squad and Paul in any way I can.

"Of course I would love to have been captain and it hurts to feel like you have been overlooked.

"But it was natural for me to feel that kind of hunger and ambition as a previous captain still playing and I would have been more worried if I hadn't felt disappointed.

"I haven't been on a tour where I haven't been a captain since the World Cup in 2003 so it'll be a little bit of a novelty.

"You'll still need experienced leadership figures not just on the pitch but throughout. Hopefully I'll be able to step up to the plate there."

McGeechan's preference for a forward to lead the Lions against the ever-muscular Springboks ultimately shaped his decision to make O'Connell skipper.

On the pitch O'Driscoll could have done little more this season to put himself in the frame as he conquered the niggling injuries that have affected his form in recent years.

Man-of-the-match displays against England and Wales in the RBS 6 Nations were evidence Ireland's Grand Slam-winning captain was almost back to his best and he added another star turn to his collection in Leinster's Heineken Cup semi-final victory over Munster last weekend.

By his own admission O'Driscoll lacks the explosive pace that marked his early Test years, instead becoming a more cerebral player who is still capable of flashes of brilliance.

Defensively he is more formidable than ever but it is maybe his uncanny knack of doing the right thing at the right time, no matter how big the stage, that sets him apart.

When it comes to delivering against world champions South Africa in his third Lions tour, O'Driscoll's temperament under pressure is guaranteed.

His previous trips with the cream of British and Irish rugby have yielded mixed results – he was superb in Australia in 2001 but his time as skipper against the All Blacks four years later ended in controversy.

The first Test was 41 seconds old when O'Driscoll sustained a series-ending shoulder injury after being spear-tackled by All Blacks skipper Tana Umaga and hooker Keven Mealamu.

"This will be a very different Lions tour for me," said the Leinster centre.

"I was very young in 2001 and then in 2005 I had the captaincy and all the additional responsibility that brings as well as the injury of course."

Despite his mixed experiences – 2005 was perhaps the lowest point of his career - O'Driscoll continues to be seduced by what the Lions represent.

"You have a grace period in the first few days where everyone's a little bit shy and things are a bit awkward," he said.

"But you'd be very surprised about how you kick into becoming a Lion.

"It's a nice place to be at when you don't look at people as English, Scottish, Welsh or Irish, you just look at them as team-mates and as Lions.

"Tours have changed and things will change again. It's a shorter period of time, it's a professional era and we play against each other a lot more.

"We possibly don't do as much socialising with each other as they did back in the day but it is such a unique thing that you never get that opportunity to play with that quality of player from other countries ever again."