Two-time Olympic champion Dame Val Adams has claimed her 16th national shot put title, but again fell to a Canadian visitor, as she continued her build-up for the Tokyo Games.
Dame Val seemed well in control at the Nga Puna Wai Stadium in Christchurch, leading after five throws with a second-round 18.73m effort.
But with the penultimate toss of the competition, Commonwealth Games bronze medallist Brittany Crew powered the implement out to 18.88m and Dame Val was unable to respond.
The defeat was her second of the summer at the hands of a North American thrower, with World University champion Sarah Mitton prevailing in Auckland two weeks ago.
Still, the performance represented Dame Val's fourth meeting over the Olympic qualifying distance of 18.50m. With a personal best of 21.24m, Adams, 35, is chasing selection for her fifth Olympics, after giving birth to two children since taking a silver medal at Rio 2016.
Blustery winds disrupted many events on the opening day of the national track and field championships.
Earlier in the afternoon, national 400m hurdles recordholder Portia Bing was two seconds outside her Olympic standard of 55.40s, recording 57.69s and winning more than three seconds.
Shotput star Tom Walsh set a seasons best throw of 21.7 in the process claiming his 11th National title
With the wind at his back, Eddie Osei-Nketia successfully defended his 100m sprint title, he got off to a lightning start and never looked back as he crossed the line with a time of 10.46.
Women's sprinter Zoe Hobbs, who had to overcame some early complications with two false starts, and some chilly conditions to pick up her 4th 100m national title with a tiime of 11.47.