Coster was one of the two-man New Zealand Shearing Sports team to tour the United Kingdom earlier this year and broke his wrist shortly before the final of the eight-match series.
At the show, Coster, finishing in 12min 36.86 seconds, not only won the 10-sheep race - 2.2 points ahead of runner-up Kirkpatrick - but also scored highest points on quality.
Event favourite Kirkpatrick was top qualifier in the heats and the semifinals whereas Coster was sixth of 32 in the heats and last of six to qualify in the semifinals.
The blades final, over five sheep, was won by Fairlie shearer Tony Dobbs. Bill Michelle, of Timaru was second, Allan Oldfield, of Geraldine, was third, and 2012 World championships New Zealand teammates Mike McConnell, of Albury, and Brian Thomson, of Christchurch, were fourth and fifth respectively.
World and Golden Shears champion woolhandler Joel Henare, of Gisborne, won the Corriedale woolhandling open title - a victory which had eluded him until now.