Seasoned breaststroke swimmer Glenn Snyders produced a top class swim on the third morning of the world championships in Kazan, Russia, and had a part in the third world record of the event.
To cap an encouraging morning, Bay of Plenty's Nathan Capp set a national record in the 800m freestyle heats.
American-based Snyders was third in his heat of the 50m breaststroke in a season-best time of 27.23 seconds, eclipsing his previous mark by .27s.
However the star turn came from South African Cameron van den Burgh, who touched in 26.62s, shaving .05s of his own previous world record, set in Rome six years ago.
Snyder was seventh fastest into the semifinals to be raced early tomorrow.
Van den Burgh's mark was challenged hard by Britain's classy Adam Peaty, who put out a 26.68s, suggesting a cracking event is under way.
Capp, who pulled out of the 400m freestyle on the opening day of competition to concentrate on today's event and his 1500m on the penultimate day of racing, recorded 7:57.61, to take .69s off his own New Zealand record, in finishing fifth in his heat, which was won by Norway's Henrik Christiansen in 7:49.70.
American Connor Jaeger was fastest qualifier in 7:44.77, about 12s off the six-year-old world best of China's Lin Zhang.
Bradlee Ashby finished fourth in his heat at his first event at the championships, clocking 2min 04.31s, about 4s slower than his season best.
It left the Hamilton swimmer 33rd overall, his heat won by Colombia's Esmaider Reales in 2:01.13, while Hungary's Laszlo Cseh was fastest qualifier recording 1:53.71 but 2s outside the six-year-old world record of American legend Michael Phelps.