Mahe Drysdale has survived pre-Christmas surgery to win a record-equalling ninth single sculls title at the national championships.
He joined Murray Watkinson, who won a nonet of titles between 1964 and 1974.
Drysdale, in addition to helping negotiate the well-documented spat between Rowing New Zealand and his coach Dick Tonks, was suffering compartmental syndrome in his forearms.
Incisions cut into the sheaths surrounding the muscle to allow more blood to flow into his hands after he experienced numbness in his thumbs during races since the Olympics.
"I was alright if I was comfortably in front, but it limited me when it came down to a sprint. I was never confident in a tight race that I could hold onto my oars.
"The muscles get too big for the sheath, so when they filled with blood in a tight race, it started cutting off nerves and I started losing the feeling in my hands. By releasing [the sheath], the muscles can expand as much as they want.
"I thought I'd sorted it out but I had more problems overseas [last year]. I raced on rough water this week, had some tight races and, touch wood, the problem seems to be solved."
Drysdale said the low-risk operation commonly occurred in rowers, kayakers and builders swinging hammers.
"I wouldn't say it was simple, but it was non-invasive. As soon as the scars healed I could go back to training. Nerve issues kept me out of the boat about two weeks."
After the operation Drysdale was unable to lift daughter Bronte, and had to treat his hands as mittens as he struggled through meals.
One of Drysdale's rivals was heard on the pontoon post-race saying the Olympic champion's recent defeats, suffered at the oars of fellow national representatives Robbie Manson and John Storey, had "woken the bear".
Manson was second in the final, 1.29s behind Drysdale; Storey was third, 6.51s back.
"This will put a bit of doubt out of the selectors' minds," Drysdale said, ahead of next week's Olympic trials and the announcement of the Rio team on March 4.
"I'm pleased with where I am at six months out. I knew I was underdone racing-wise, but today showed I can pull out a big race.
"We're so lucky in New Zealand with our great system training against each other. There's always been someone to push me along, which is an advantage we have over other countries. It goes back through the likes of [single sculls challengers] Nathan Twaddle, Nathan Cohen, Hamish Bond, Robbie Manson and John Storey. And every day in training Zoe [Stevenson] and Eve [Macfarlane] keep me honest in the women's double.
"While I'm in good shape, there are guys who can come out and beat me now. That reflects how good the squad is.
He said the Tonks dispute, which saw the coach axed as an employee then reinstated as a contractor, had ultimately not been disruptive.
"As athletes it doesn't feel like anything's changed, which is exactly the result we wanted."
Emma Twigg won the women's single sculls for the seventh time, equal with Brenda Lawson but two shy of Stephanie Foster's nine titles secured between 1978 and 1986.
The Central and Waikato regional performance centre crews won the respective women's and men's eights.
- By Andrew Alderson at Lake Karapiro