[1] Petrik began his coaching career with the Rockingham Flames men's team in the State Basketball League (SBL).

[3] In his first season as head coach, he led the team to one of their best ever performances with a third-place finish and a 15–7 record with no imports and just one national league player.

[17] In 2021, Petrik guided the men's team to their first ever grand final in the inaugural NBL1 West season, where they lost 92–82 to the Perry Lakes Hawks.

[25] In October 2023, Petrik signed a two-year deal with the Flames to remain as men's head coach until the end of 2025.

[26] In June 2015, Petrik was appointed an assistant coach to the Perth Lynx of the Women's National Basketball League (WNBL).

[27][28] In June 2020, after five seasons as an assistant under Andy Stewart, Petrik was appointed head coach of the Lynx on a two-year deal.

[40] In the 2023–24 season, the Lynx finished in fourth place with an 11–10 record and defeated the first-placed Townsville Fire in the semi-finals to reach their second grand final series in three years.