Mattner during these two years was still young, and was playing well for his local SANFL club Sturt, regularly gathering 20 or more disposals a match as well as laying many bone-crunching tackles. In the 2002 SANFL season, the Double Blues won the premiership over Central District and Mattner was listed among the best players in the Grand Final. Sturt's end of season trip was to Bali. Team members were caught up in the 2002 Bali bombings and fellow player Josh Deegan and club official Bob Marshall were killed.