 1993 saw Mackay continue his good form and he was the starting lock forward for NSW in all three State of Origin games in the Blues 2-1 series win over Queensland.The return from injury of Bradley Clyde would see Mackay on the bench for Australia in the 1st and 3rd Trans-Tasman Tests against New Zealand.Later that year he became one of only four players (the others being Bradley Clyde in 1991, Daly Cherry-Evans in 2013 and Jack Wighton in 2019) to win the Clive Churchill Medal from the losing side when the Dragons went down 6-14 in the Grand Final, again to the Brisbane Broncos.