He failed to round a buoy in the last round in Wellington and had to settle for third place.
"I know that in order to win the series, I'm going to have to win three of the races," he said.
"I'm well aware of that, but at the end of the day it's really just about getting out there and gaining more experience in open water."
Radford wants to win but is not taking his eye off the ball in terms of the big picture - which is the London Olympics. After winning the New Zealand 10km open-water title last month, he will head to the final Olympic qualifier in Portugal in June.
"So Sunday isn't so much really about redemption for me. It's another swim, and I'll learn more from it and keep on moving forward.
"Everything's looking really good leading into Portugal. I've just got a lot of hard work to do between now and then."
Radford will not be freshening up for tomorrow. Far from it.
After competing in the New South Wales Championships in Sydney, he returned to join the Swimming New Zealand High Performance Squad in a training camp at his home city of Rotorua.
It's been a huge week of mileage under coach Mark Regan, but Radford says it is all part of the process for his improvement as a swimmer.
"You have to cope under different situations and know how well you can cope when you are tired, so it may have a little effect, but at the end of the day you can't really use that as an excuse.
"I'm definitely looking to win it, as I always am when I go into these races."
The event, a year on from the disastrous second major earthquake in Christchurch, has not gone unnoticed by the champion swimmer.
"I think it's great that the series is still going down there this year. It will be great for the people of Christchurch just to have something else to somewhat look forward to.
"So hopefully everyone can get down there and support it.
"Everyone who is going to be down there is a quality swimmer and on their day could have a great day; you never know."
State Ocean Swim Series:
www.oceanswimseries.co.nz
