Kyle Chalmers reckons being old is an advantage.
The Australian enters the 100 metres freestyle final at the world championships in ripping physical nick.
But he believes Thursday night's coveted gold medal will be won by the mind, not matter.
The 25-year-old is the oldest swimmer in a Fukuoka field including 18-year-old world record holder David Popovici.
"I will be the oldest person in the race, I have been through it quite a few times," Chalmers said.
"And I understand that heat, semi-final process a whole lot better now.
"Physically I feel really good - I have been able to get through both of these rounds with very minimal mental or emotional energy put in.
"Physically, obviously you have to put in a little bit to swim that fast but I was able to get through those two rounds with that in the tank.
"And (in the final) I know that I can put all my emotional energy into swimming fast."
Chalmers qualified second-fastest for the final as he bids to claim the 100m freestyle world title for the first time, after coming second in 2019.
Other Australians chasing medals on Thursday night are Liz Dekkers in the women's 200m butterfly and Kaylee McKeown in the women's 50m backstroke.
Zac Stubblety-Cook will start his campaign in his pet event, the 200m breaststroke - the world record holder and Olympic champion a firm favourite ahead of Thursday's heats and semi-finals.
And Mollie O'Callaghan, fresh from setting a world record in the 200m freestyle, begin her 100m freestyle program with heats and semi-finals alongside compatriot Emma McKeon.
O'Callaghan said her 200m feat on Wednesday night, when she broke the longest-standing record in women's swimming, was unexpected.
The 19-year-old clocked one minute 52.85 seconds, bettering the 1:52.98 set by Italian Federica Pellegrini in the supersuit era in 2009.
"I am just so proud of myself to do that," she said.
"It was such an unexpected moment."
