Football Federation Australia (FFA) have put the Western Sydney Wanderers on notice after their hopes for a flare-free A-League season fell at the first hurdle.
After Wanderers fans lit and threw a small number of flares in their 4-0 Sydney derby loss, FFA on Monday issued the club with a show cause notice that will extend -- but not trigger -- the threat of a three-point deduction until the end of the season.
According to the governing body, the Wanderers have accepted the result and will re-double their efforts to maintain crowd decorum for the season ahead.
While police were largely comfortable with the crowd behaviour in Saturday's derby, the flares embarrassed club leaders.
A letter from figures including chief executive John Tsatsimas, coach Tony Popovic and captain Nikolai Topor-Stanley asked fans to be on their best behaviour this season.
"As a club we are united to succeed on the pitch and have a flare-free season," the letter read.
The Red and Black Bloc's restraint lasted less than an hour.
A-League chief Greg O'Rourke said he didn't want to see similar incidents.
"If there's a recurrence of the incident from last Saturday night ... FFA may well be left with no alternative other than to deduct points from the club," he said.
"The club will reconnect with their members again this week given a few persons chose to ignore the communication and strong stance against the lighting of flares from Tsatsimas, head coach Popovic and captain Topor-Stanley."
The Wanderers were originally served the punishment after away fans ignited about 20 flares, as well as crowd-frightening detonators, during a match against Melbourne Victory at Etihad Stadium in February this year.
The ban was due to expire next February but will continue until after the last round of the regular season in April.
Melbourne Victory are also sweating under the threat of a points deduction until next February for crowd trouble.
The incident was a bum note in an otherwise stunning opening round, which attracted a league-record 106,365 attendees to the five matches.