Former Test quicks have urged Brett Lee to improve his average or forget about succeeding Glenn McGrath as Australia's pace spearhead.
Lee finished the Ashes series with 20 wickets at a respectable average of 33.20.
But Jeff Thomson and Damien Fleming insist Australia's fastest bowler must do better to fill the void left by McGrath.
McGrath ended his 124-Test career on Friday with 563 wickets at the magnificent average of 21.64.
"If Brett's a spearhead he can't be averaging over 30 with the ball," said Fleming, who took 75 wickets in 20 Tests at 25.89.
"History shows the great bowlers and the best spearheads average at least under 25.
"It would probably be too much for us to say Brett Lee must get his career average under 25 in the next two or three years.
"But what Brett must do from now is average under 25 and take on average about four wickets a Test. That's what a spearhead must do and I think Brett is capable of doing that."
Since his debut against India in 1999, Lee has claimed 231 Test victims, placing him eighth on Australia's list of all-time wicket-takers.
The 30-year-old finished the Ashes impressively in the fifth Test, taking 3-75 and 3-39 to play a vital role in the 10-wicket victory.
But his career average of 31.60 has prompted critics to suggest he lacks the consistency, if not pace, to become the cornerstone of Australia's bowling attack.
"I don't think Brett Lee has convinced anybody. He hasn't convinced me," Thomson said.
"He's got to up the ante now. He needs to bowl more quality. He has to bowl the way he bowled in the first and second innings of this (fifth) Test.
"Coming into this Test, he was averaging nearly 40. That's not good enough. He just bowls too many balls that are non-effective.
"Stuart Clark has come into Test cricket and bowled him off a break because he bowls better quality.
"Brett has been around long enough to know what he's supposed to bowl.
"I'd like to see Brett succeed but he needs to change. He needs to concentrate on bowling tighter and cut out the poor-quality balls.
"Lee's youth has kept him in the side before but, without the protection of Warne and McGrath, he has to start pulling his finger out or he will come under the pump."
Fleming said the emergence of Clark could be critical to Lee.
"The key is having partnerships and I think Stuart Clark can be a great support," he said.
"It would be tough if Lee had to do it himself but having a guy like Stuart will complement his express bowling.
"I think the extra responsibility can help take him to the next level."
- PETER BADEL