Jonathan Sexton will be seeking to prove Ireland have a genuine alternative to Ronan O'Gara when he makes his Test debut against Fiji on Saturday.

Sexton replaces O'Gara, who drops out of the squad, at fly-half as one of eight changes to the side which drew 20-20 with Australia.

It is reward for the 24-year-old's sparkling provincial form which reached its zenith during the closing stages of Leinster's march to their first Heineken Cup crown last season.

Initially considered third-choice fly-half, he showed remarkable maturity when a knee injury to Felipe Contepomi saw him pitched into action early on in the semi-final against Munster.

A similar display against Leicester in the final and a solid start to the current campaign has convinced national coach Declan Kidney he is ready to be promoted from the bench.

Sexton will have the luxury of appearing in a virtually all-Leinster back line - Munster winger Keith Earls breaks their monopoly - and is delighted to realise his boyhood dream.

"This is a very proud moment for me and my family. This is different to winning the Heineken Cup, which is a team thing," he said.

"Getting selected by Ireland is a personal thing but is something I've wanted since I was a kid.

"I've focused on not trying as hard to make things happen. I was trying too hard at the start of last year.

"I've relaxed a bit and I'm not concentrating on the mistakes I make. I have a more positive outlook."

Sexton has been the subject of a growing clamour demanding his Test inclusion as Ireland acknowledge time is running out to uncover O'Gara's successor.

O'Gara's dominance of the number 10 shirt has been so complete that until Sexton's emergence as a credible option during the last six months, the position has been damned by a critical lack of depth.

Munster's long-serving Lion will be 34 by the next World Cup so Sexton's development is crucial, but his Leinster and Ireland captain Brian O'Driscoll is confident he will make a smooth transition.

"Jonathan is a very talented player but also has a strong work ethic. He puts a lot of thought into his game," said O'Driscoll.

"He does a lot of background work and we knock him for having an encyclopaedic knowledge of games we've been involved in. He can recall crazy things!

"It's been a huge six months for him, coming in at the semi-final of the Heineken Cup and controlling things the way he did.

"Then he gave a big performance in the final. This year he has been very solid and controls things well.

"With every game he's getting better and he has a great future in Irish rugby."

Earls, who replaces the injured Luke Fitzgerald, is the only non-Leinster representative in the back line with Gordon D'Arcy, Shane Horgan and Eoin Reddan recalled.

D'Arcy deputises for Paddy Wallace at inside centre, Horgan comes in for Tommy Bowe on the right wing and Reddan is given the nod ahead of Tomas O'Leary at scrum-half.

O'Driscoll, who celebrated his 100th Test appearance with the match-saving try against Australia, will captain the team for the 58th time.

Ulster's Tom Court starts ahead of Cian Healy at loosehead prop while Leo Cullen partners Paul O'Connell in the second row with Donncha O'Callaghan dropping to the bench.

The final change sees Denis Leamy displace Munster colleague David Wallace at openside.

Healy is nursing a shoulder injury but should be available to face South Africa a week on Saturday.