After years of being ridiculed over his batting, Australian fast bowler Glenn McGrath finally proved his detractors wrong on Saturday by scoring his maiden Test fifty.

The lanky paceman brought up the milestone in his 102nd Test when he struck New Zealand left-arm spinner Daniel Vettori for successive boundaries and he ended day three unbeaten on 54.

Beaming with pride, McGrath followed a ritual most observers thought he would never experience when he took off his helmet and raised his bat in triumph.

"That was better than getting a big wicket haul," McGrath chuckled. "It's been a long time coming."

The Australian dressing room also burst into celebration when McGrath reached the magical milestone, players hugging each other and slapping high-fives.

Michael Clarke, Australia's latest batting sensation, had scored 141 earlier in the day in his first Test on home soil but was more excited by McGrath's achievement.

"That's the best thing I've ever seen in cricket; it was just unbelievable," Clarke said. "When he went out to bat, we all started getting ready to field because we thought he'd be back in a minute."

Australian leg spinner Shane Warne cheered louder than most. Years ago, he waged a bet with former Test batsman Mark Waugh that McGrath would eventually score a first-class fifty.

McGrath said Waugh did not pay up when he scored 50 in a county match in England four years ago, but added that he would have to honour his achievement at the Gabba.

McGrath is one of the world's greatest bowlers but has never shown much ability with the bat. He averages less than seven in Test cricket and had passed 30 only once before, reaching 39 against West Indies five years ago.

'BATTING BUNNY'

He had taken almost as many wickets as he had scored runs and was often described as a "batting bunny". Steve Waugh tried coaching him but eventually gave up, telling McGrath to try batting left-handed because he could not do worse.

While Australia's players have all signed lucrative batting sponsorship deals, McGrath walked to the crease with a bare blade until his batting career took an unexpected twist.

A serious ankle injury forced the fast bowler to miss almost a year's Test cricket. He was told not to run while the ankle healed, and started practising his batting instead.

"I was doing two sessions a week, hitting about 500 balls each time, so eventually I had to start hitting them alright," he said.

McGrath has often been the non-striker trying to help established batsmen reach their hundreds in Tests but he had only fellow bowler Jason Gillespie to assist him when he strode to the crease after tea on Saturday.

Gillespie only averages 14 in Tests and has a career-best score of 48 not out but he has a sound defensive technique and the two lanky bowlers made a mockery of their modest statistics with an enthralling 93-run stand in 110 minutes.

Gillespie was 43 not out at the close of play and McGrath said he planned to help his fast bowling colleague also reach his maiden Test 50.

"It was good to get to a milestone myself but I feel a bit nervous. I don't want to get out and cost Dizzy [Gillespie] a fifty," McGrath said.

"I don't know what it was but I just had a feeling today could be the day."