"To be a fast bowler you have to have that aggression. It's a naturally aggressive part of the game and if you are running in and bowling and smiling at the batsman when they hit you for fours, you are not going to stay there for long, are you?" he said.

McGrath expects left-arm pacer Mitchell Johnson to lead the depleted pace battery from the front. "Mitchell should lead from the front to set the tone. Obviously Mitch isn't an old bloke himself so it will be a learning experience for him as well," he said.

With Brett Lee injured and struggling, 17-Test-old Johnson, who started his career under McGrath, now finds himself with the extra burden of leading an inexperienced Australian pace attack.

But McGrath feels the 27-year-old left-arm pacer will thrive on the opportunity. "Some guys thrive on it, they love that responsibility of being the number one bowler. Any bowler should strive to do that, I think Mitchell will obviously enjoy that," he was quoted as saying by the 'Herald Sun'.

"The way that Johnson has bowled this year has been sensational. To see him come up, he always had the potential, and now he has the confidence," he added.

McGrath, who ended his career with 563 Test wickets, feels that the present vacuum in Australia's pace department has opened up window of opportunity for young quicks.