In the open final, Jones shore 13m 14s, with Fagan next off in 13m 26s.
Jones is also currently eyeing up a world two-stand lamb shearing record attempt with Abraham in New Zealand.
With wins against England and France on tour, New Zealand manager Mark Barrowcliffe said it was “a day of high hopes” that ended with the Kiwis getting dominated in the test and open final.
“The Welsh boys all shore really well and the home crowd really pulled their team along,” he said.
“But once again getting both team members into the open final was a huge achievement from a top field.”
The second test, with Fagan and Buick trying to get New Zealand’s first series win in Wales since 2019, is at the Royal Welsh Show on Wednesday, against a Welsh team decided at the show for the match and the final test at the Corwen Shears next Saturday.
Results from the Cothi Shears, Wales, Saturday, January 20, 2024:
First test (20 sheep): Wales (Llyr Jones 13m 31s, 51.35pts; Gethin Lewis 14m 11s, 51.95s) 103.3pts bt New Zealand (Jack Fagan 14m 44s, 53.1pts; David Buick 14m 5s, 57.45pts) 110.55pts.
Cothi Open final (20 sheep): Llyr Jones (Wales) 13m 14s, 48.75pts, 1; Richard Jones (Wales) 14m 33s, 51.15pts, 2; Jack Fagan (New Zealand) 13m 26s, 51.85pts, 3; Gwion Lloyd Evans (Wales) 14m 21s, 53.65pts, 4; David Buick (New Zealand) 14m 53s, 56.15pts, 5.