Ross Murdoch says reaching an Olympic final would be a "dream come true" but realises he may need the best performance of his career to get there.
The 27-year-old Scot has been selected for the 200m breaststroke in Tokyo.
This will be his second Games, having missed out on the final in the 100m event at Rio 2016.
"It's going to difficult; in the past five years the world of swimming has moved insanely fast," Murdoch told BBC Scotland.
"To swim in an Olympic final would be a dream come true.
"The time I won the 2014 Commonwealth Games in, you might struggle to make the final with that. I'm probably going to need a lifetime best to make the top eight, but that has to be the aim.
"The 200m breaststroke gold was won from lane eight in 2016, so if you've got a lane, you've got a chance."
Murdoch admits his Rio experience was "underwhelming" but has rediscovered his love for the sport after a period of doubt.
"I wasn't even sure I was going to keep swimming to be honest, but five years and a lockdown later, I'm still here and I definitely feel like I've got more to give," he said.
"I was out of the water for 15 weeks during lockdown, but I got back to fitness and made it through the Olympic trials by .07 seconds.
"Off the back of 2014, looking back at 2015, that's when I should have recognised I was having some issues. I wasn't dealing well with success. I just wasn't entirely happy with what was supposed to be this massive thing for me. Rio was just the cherry on top of that cake.
"But I forced myself to get back in the water and I would always feel miles better after training. We have a great squad at Stirling University and that's the main reason I'm still going.
"I took to running during the first big lockdown and absolutely loved it. It felt like meditation to me, a time to organise my thoughts. It has helped give me more focus and made me think about my life differently and give me more appreciation of the experiences I've had."