Australia's greatest run-scorer announced on Thursday that he would quit the international game after the deciding Test against South Africa at the WACA Ground, starting on Friday, which was already an unofficial world championship but is now even more significant as Ponting's farewell.

The 37-year-old former captain said inconsistency and failure to reach the heights of his storied career had prompted him to bring his remarkable 17-year Test career to a close. In an ideal world, Ponting would have carried on to England for next winter's Ashes rematch but he conceded his game was no longer up to it.

''It's not tough at all [missing the Ashes] because I've made up my own mind that I feel I'm not good enough to get there,'' Ponting said.

''When you come to the realisation that what you can give is probably not good enough, then it's a pretty easy decision.''

Having scored only 20 runs in three innings in the series against South Africa and facing renewed questions about whether age had caught up with him, Ponting began to consider retirement during the second Test in Adelaide which ended on Monday. After speaking to Australian selectors and captain Michael Clarke there about his future, he was locked in introspection since, before confirming to the team hierarchy on Wednesday that he would not play beyond Perth. The timing was entirely of his making, he insisted, and not the selection panel. He jumped, and was not pushed, he said.

''This is not a decision that's been made by the selectors, by the way,'' Ponting said. ''This is a decision that's been made by me. It was towards the end of the Adelaide game when I first started contemplating what it might mean and … if I believed in myself if I was good enough to play the way that I've been known to play through the years.

''The thing that struck home for me was that only a few weeks ago I felt that my preparation had been as good as it's been for a while. My [Sheffield] Shield form had been good, I'd scored runs, and felt good about my batting. But when the big moments came around I haven't been able to deliver what's been required for the team.

''I've had moments of really good stuff and I've had prolonged moments of cricket that's been below expectations and below a par level for me. At the end of the series it will give whoever my replacement is the chance to start afresh in a new series.''

Ponting will play out the season with Tasmania and in the Big Bash League with Hobart Hurricanes, and exits international cricket with a reputation and records few have rivalled. His 13,366

runs in Tests make him Australia's most prolific batsman of all-time, and the second outright behind India's Sachin Tendulkar. He is also the most successful captain in Test history, winning 48 of his 77 Tests in charge, owns the most victories by an individual and in Perth will equal Steve Waugh's Australian mark of 168 Test caps. Ponting also won three World Cups, captaining Australia in two of them.

His Test career was given new life last summer when he produced a drought-breaking century against India at the SCG, and then followed it with a double century, the sixth of his career, in Adelaide. Since then there has been only one 50 in nine innings but while the reflexes might have slowed and the bat might not strike the ball quite as crisply, the fire still burns. He is desperate to leave with Australia once again on top of the Test world rankings, which will happen if it beats South Africa in Perth to win the series.

''I'm hungrier than ever and want this win probably more than any game I've ever played in,'' Ponting said. ''As far as I'm concerned, my immediate focus now and I know the team's immediate focus is what we're presented with tomorrow. If we win then there's no better time to give it away anyway. We're going into what I believe is almost a grand final.

''I've got to lift my level of play from where it was last week to another level this week. There is no better stage than in a finals-type game, a big game, games that I've always prided myself on playing well in, to try and do that this week. My passion and love for the game hasn't changed one bit right through the last 12 or 18 months where things probably haven't been as I would have liked.''

Ponting's announcement, while not entirely unexpected, hit his teammates hard. An emotional Clarke could only speak for so long as he followed Ponting to the microphone.

''The boys are obviously hurting at the moment. He's been an amazing player for a long time,'' Clarke said. ''I think it will only give us more inspiration, there is no doubt about that.''