|By HAMISH NEAL
Mariners youngster Bernie Ibini scored 15 minutes after coming on in the second half as the men in navy and yellow moved to 30 points after 14 games.
Ibini chested down a cross from Oliver Bozanic before slotting home the match-winner with his left foot in the 68th minute for his third goal of the season.
To rub salt into the wound for the visitors, Perth defender Bas Van Den Brink will miss the visit of Sydney FC after he was sent off for two bookable offences, the second of which came in the 76th minute after a foul on Mile Sterjovski.
A busy period of games, coupled with suspensions and injuries, saw a combined eight changes between the two sides.
Ibini, 20, was benched in favour of Sterjovski and in defence Pedj Bojic (returning from suspension) replaced Hayden Morton.
Graham Arnold also brought in Bozanic, Adam Kwasnik and Adriano Pellegrino to start for the suspended trio of Tomas Rogic, Daniel McBreen and John Hutchinson.
Perth replaced the injured Michael Thwaite with Scott Jamieson plus Steve Pantelidis and Travis Dodd came in for Chris Harold and Ryo Nagai.
Ian Ferguson's men dominated the early possession but neither side was able to get a shot on target in the first half.
The best chance for the Mariners came in the 17th minute when Bojic set up skipper Michael McGlinchey when he made a run beating two Perth defenders, but McGlinchey was unable to connect with the ball.
Shane Smeltz missed the half's best opportunity in the 36th minute when he was unmarked at the far post. After a cross from the left side of the penalty box from Steven McGarry the Kiwi marksmen put his volley from about six metres out wide in an uncharacteristic error.
The Mariners had a chance in first-half injury time after a Joshua Rose cross fell to Kwasnik but former Mariners goalkeeper Danny Vukovic made a clean save.
Mariners captain McGlinchey was in the action again after the break as he was brought down 30 metres out from goal by Van den Brink, his first booking of the night. However, Bojic was unable to capitalise as he put the resultant free-kick well over the cross bar.
After Ibini's match-winner and Van den Brink's dismissal the chances continued to come primarily for the home side.
Defender Trent Sainsbury headed over a good chance in the 80th minute and Sterjovksi also forced a Vukovic save.
Despite some late Perth pressure the Mariners held on for the triumph.