Missing players due to suspension and disciplinary reasons, a hugely inexperienced Mariners side were carved apart by two-goal Phoenix striker Roy Krishna and his attacking cohorts.
Down 4-0 at half time, the home side were 7-0 down by the 59th minute mark and looking likely to suffer by an all-time A-League record losing margin, with the previous mark set by Adelaide United who secured an 8-1 win over North Queensland Fury in 2011.
Yet it was the Phoenix who went into the contest in freefall, having won just one of their last seven matches and in danger of ceding their spot in the top six to Newcastle Jets.
Mike Mulvey's half time talk clearly had little impact as Liberato Cacace, Sarpreet Singh and Louis Fenton all netted by the hour mark.
The Mariners netted two consolation goals against the run of play, firstly through full-back Jack Clisby and then via a fine Stephen Mallon free kick.
The result sees the Phoenix leapfrog Melbourne City and Adelaide United up to fourth on the ladder -- the latter on goal difference. The scoreline also equals the competition's biggest scoring match when the Mariners crashed to an 8-2 home loss against Newcastle Jets just 11 months ago.