Ireland 20 Australia 20

Ireland's Brian O'Driscoll scores a last-minute try to ruin Australia's hopes of a grand slam. Photo / Getty Images Expand

Ireland's Brian O'Driscoll scores a last-minute try to ruin Australia's hopes of a grand slam. Photo / Getty Images

DUBLIN - Brian O'Driscoll marked his 100th cap with a try in the last second of the game to rescue a 20-20 draw for Ireland against Australia today.

The scoreline was hard on the Wallabies who were the dominant force up front and made more line breaks against a rusty-looking Irish outfit playing their first game of the season.

Australia had led 10-6 at halftime with Drew Mitchell scoring a try.

Tommy Bowe then scored for Ireland in the second half before Wallabies skipper Rocky Elsom also went over for what looked like the game winner with his team 20-13 in front.

Matt Giteau kicked 10 points while Ronan O'Gara hit two penalties and two conversions for Ireland, the Six Nations champions.

The result shattered Australia's hopes of achieving a Grand Slam of wins over all the home nations on this tour after starting with a win over England last weekend.

"If we had defended that last phase, we would have deserved to win but who would have thought, in his 100th game, Brian would come up with the goods?," said Elsom.

"I thought we could have stopped that last play but they executed really well."

Any hopes of the Irish making a fast start were scuppered in the third minute when Mitchell ran in unopposed for a try after O'Driscoll failed to hold a poor pass from O'Gara.

O'Gara responded almost immediately with a penalty almost straight in front of the posts.

Australia looked sharper and stronger in the opening quarter and Giteau failed with a difficult penalty chance in the 16th minute as Ireland struggled for possession.

Giteau's miss marked Ireland first period of multi-phase play putting the ball through hand going right and left.

A scrambling Wallaby team were eventually forced to concede a penalty in front of the posts allowing O'Gara to bring arrears back to one point by the end of the first quarter.

Giteau hit back immediately after the Irish committed an offence to stop the Australian pack again securing turnover ball.

But just when it looked the Wallabies had wrestled control back from the Irish, Wycliff Palu thundered shoulder-first into Rob Kearney, doing more than stop the full-back's momentum.