Terry Antonis soared from villain to hero, scoring the winning goal deep in extra time to put Melbourne Victory into the A-League grand final and dump out defending champions Sydney FC on Saturday.

Victory won a drama-charged semi-final 3-2 and will now face the Newcastle Jets in Newcastle next Saturday to decide this season's champion.

Antonis was in the depths of depair when he scored an own goal with seconds left in regulation time to give Sydney FC the equaliser and a lifeline into extra time.

Just when Sydney were expected to go on and win the match, midfielder Antonis fired home the winning goal deep into the second period of extra time.

His goal sparked dramatic scenes with two Victory assistant coaches -- Jean-Paul de Marigny and Dean Anastasiadis -- dismissed for overzealous celebrations on the pitch after the winner.

It will be an unprecedented sixth grand final berth for Victory while Sydney FC, who had won their previous seven games against Victory and finished 14 points clear at the top of regular season standings, will miss out on the decider.

A stunning "scorpion" goal from youngster Riley McGree lifted the Newcastle Jets into their first grand final in 10 years on Friday.

McGree, 19, on loan from Belgium's Club Brugge, scored the equaliser with an audacious flick from behind his body to inspire the Jets to a come-from-behind 2-1 win over Melbourne City in a gripping semi-final.