Glenn McGrath dismissed worries about his age after taking two wickets in his first Test appearance since January.
McGrath ended the second day's play with figures of 2-25
He removed Andrew Strauss and Alastair Cook as England floundered late on day two of the first Ashes Test.
"If you lose to a bunch of old people, it's probably worse," said the 36-year-old, one of half a dozen veterans in the Australia team.
"If I am happy with where I am going, the press can write and people can say what they want about me."
McGrath now has 544 Test wickets and is the most successful seam bowler in the history of Test cricket.
We won't be taking it easy for the rest of this Test or the series
However, before the series there were claims that time had caught up with him after 13 years at the top, and he admitted the early wickets had given him a boost on his return to the Test arena.
"To get a couple of wickets early on always does wonders for the confidence," said McGrath.
"I was probably 95% happy with how I bowled. I think I'm that close [he held his fingers an inch apart] to being where I want to be.
"Looking forward I think I can really nail it on Saturday. We want to go out and show them why we are the best team in the world."
At 6ft 5in, one of McGrath's main weapons is the lift he can generate and he said the Gabba wicket was helping him get full value.
"We haven't bowled on a wicket with that sort of bounce this season - guys like myself and Stuart Clark really enjoy wickets that have that bounce," he said.
"If we can remain patient, build up pressure, then the wickets will come."
We've definitely got a lot of momentum now and the confidence is with us
Australia won the first Test of the last Ashes series before going on to lose in England 2-1.
And McGrath was keen to stress that for all Australia's early dominance this time round, the job of winning the Ashes back is far from done.
"We've definitely got a lot of momentum now, and the confidence is with us," he said.
"But you only have to look back at last year's first Test at Lord's where we had momentum.
"We'll be trying to drive it home. A lot of times in Australia, when we go one-up, there's not too many series we lose.
"We won't be taking it easy for the rest of this Test or the series."