1989 proved to be his breakout year as he performed brilliantly, playing 31 games including Port's demolition of North Adelaide in the Grand Final and finishing second in the Magarey Medal count behind Gilbert McAdam.
In 1990 Tregenza once again starred, playing in yet another flag and again finishing second in the Magarey Medal count, this time to teammate Scott Hodges.
For years Tregenza remained a valued first teamer before an ACL tear suffered in the Round 2, 1996 victory over Fitzroy marked the turning point of his career.
"While they have played nine years, and not the 10 as required normally, the board's view is that as foundation squad members, and given their service during the tough times in the establishment of the club, they are worthy recipients of this honor", said then CEO Bill Sanders.
[4] Following his retirement from football, Tregenza took up coaching Sacred Heart Old Collegians in the South Australian Amateur League where he guided the club to the 2001 Premiership.