O'Gara's place in Ireland's XV is by no means certain as Sexton started three of Ireland's five matches in the 2011 Six Nations © Getty Images

Enlarge

Related Links

News: D'Arcy struggling to make World Cup

News: Ferris targets August comeback

News: D'Arcy goes under the knife

News: Horgan suffers Rugby World Cup blow

Features: O'Brien the leading Irish light

Reaction: Leinster run out of steam

Match Pack: Munster power to Magners title

Preview: Leinster eye historic double

Features: Leinster's best Lazarus impersonation

News: Sexton inspired by sporting history

Players/Officials: Declan Kidney | Ronan O'Gara | Johnny Sexton

Tournaments/Tours: Rugby World Cup

Teams: Ireland | Leinster | Munster

Ronan O'Gara is backing himself to be fit for Ireland's opening Rugby World Cup clash against the USA despite suffering an injury in training.

The Munster fly-half tore his calf earlier this month during Ireland's first World Cup training camp at Carton House but the veteran insists he is winning his fitness battle although a little wary of rushing back from injury.

"I hurt myself on the last day in Carton House," O'Gara told the Irish Independent. "I tore my calf running. I just pushed the body so hard in the first week that I got a bit of a twinge.

"I'm nearly back, but I haven't done much running for the last 10 days. I'm playing catch-up; most definitely the lads are ahead of me. They will have had four heavy fitness sessions on me and the sessions look really hard, so I'll have to make that up. But I wouldn't give too much thought to something like that."

The battle for the Ireland fly-half berth is intense with O'Gara vying with Leinster's Jonathan Sexton for the starting spot. Sexton started three of the five 2011 Six Nations matches and produced a man-of-the-match performance against England as they dashed their rival's Grand Slam hopes. O'Gara is relishing the challenge from his 26-year-old counterpart.

"There is the jersey up for grabs, there are two of us fighting for it," O'Gara said. "I couldn't be happier with the way things are going. I'll be looking to make an impact and that is the bottom line. I'll make sure I'm in good condition physically and mentally and I haven't really thought about the competition for the jersey.

"What sport has told me is it's very rare that I don't have an impact in games and I've got to be ready for that. There will, hopefully, come a time in the World Cup that I'm needed, whether it is to start games or come on and win games. It's all to play for. It just makes the debate more appealing to everyone at this stage."

Ireland face against Scotland at Murrayfield on August 6 in the first of four warm-up matches before starting their World Cup campaign against the USA in New Plymouth on September 11.