Malivak netted in the 48th, 68th and 82nd minutes as the 1994 runners-up twice came from a goal down in an ill-tempered match to clinch a place in the semifinals on the weekend of August 29.
Forrest Hill gave their vocal home support something to celebrate with Mikael Munday's opening goal after just over 10 minutes. Only a pair of sharp saves from Nick van Hattum kept Olympic in the match until they finally found their legs and equalised through Malivak three minutes after the break.
Former All Whites striker Brent Fisher produced a deft header on the hour to restore Forrest Hill's lead but Malivak's second and third strikes swung the game firmly towards Olympic.
Jimmy Halikias, provider for two of Olympic's first three goals, claimed one for himself with an 88th minute free kick that deflected wickedly over Tamati Williams.
Sheldon Pillay blasted in from close range to close the gap for Forrest Hill in injury time for a purely consolation goal.
On Saturday, Miramar enjoyed an easier time against fellow three time Chatham Cup winners Waitakere City, winning 3-1 at Wellington's David Farrington Park.
In other Saturday games, Auckland sides Manurewa and Three Kings United won quarterfinal thrillers to knock the remaining two South Islands sides out of the Cup.
Three Kings came from a goal down at Dunedin's Caledonian ground to finally prevail 4-3 in extra time over Caversham with Luiz Del Monte striking the winner in the 112th minute.
Manurewa also left it late before edging Nelson Suburbs 3-1, Dave Allen was the hero with a decisive 90th minute strike to keep his team on track for a third Cup title.
The draw for the semi finals will be made on Tuesday with the Chatham Cup final scheduled for the weekend of September 19.
