Rising sprint star Rohan Browning insists the best is yet to come after coming up just short in his bid to become the first Australian man in 65 years to contest an Olympic 100m final.

The 23-year-old Sydneysider was left to rue a slow start after finishing fifth in 10.09 seconds in his semi-final on Sunday evening in Tokyo.

Only 24 hours earlier Browning had improved to second on the Australian all-time list by winning his opening-round heat in 10.01, raising hopes he could join countryman Patrick Johnson as the only members of the exclusive sub-10 second club.

"I'm disappointed," he said.

"I think I had a better run in me than 10.09 but I gave the field too much ground early on and you can't do that in the semi-finals of the Olympic Games.

"Sometimes you nail it, sometimes you don't; that's championship racing.

"Small margins matter and you've just got to be better on the day.

"I've always thought this sport is all about consistency rather than one-off major times.

"I've been very consistent around that 10.0 point.

"That's where you need to be to run sub-10.

"I'm not quite there but hopefully not far off."

British sprinter Zharnel Hughes won the semi involving Browning in 9.98, but it was Italian Lamont Marcell Jacobs who claimed a shock gold medal later in the night in 9.80.

Despite the understandable initial disappointment from Browning, it was still a huge step forward on the global stage.

"I feel like this season I've had all the component parts of the race - it has been about putting it together in one run and it is coming," he said.

"But that's part of figuring out the event and racing at this championship level.

"In 2019 (in Doha) I ran basically dead last in my heat at the world championships, so I'm heading in the right direction."

Browning is already looking forward to a packed schedule next year taking in the world indoors in Belgrade, the world championships in Eugene, Oregon and the Commonwealth Games in Birmingham.

"I'll go and run the circuit in Europe as well, I'm definitely looking forward to that," he said.

"I do believe I belong at this level.

"A load of people were saying Tokyo has been given the soft Olympics, but I think the heats were the fastest ever and I'll take this as a learning experience.

"I was never going to be happy unless I won every race - whether that's a reasonable expectation or not - but that's what athletes expect of themselves."

The last Australian man to contest an Olympic 100m final was Hec Hogan, who won bronze in the 1956 Melbourne Games.