Last season's A-League strugglers Central Coast have started the new campaign in ignominious fashion, suffering a 2-1 FFA Cup defeat to semi-professional Melbourne club Green Gully.

The Mariners seemed set for a scrappy victory on Tuesday night in Melbourne until the home side drew level with five minutes remaining. Green Gully midfielder Liam Boland then netted a memorable 40-metre extra-time winner that would not have been out of place on any stage.

New signing Blake Powell put the A-League side in front early and, while Green Gully's equaliser was clearly offside, it was the Mariners' Ivan Necevski who was the busier of the two goalkeepers overall.

It is only the second time in the three-season history of the FFA Cup that an A-League side has been defeated by lower-league opposition.

Liam Boland scored a world-class goal to put his side through. ( Getty Images: Michael Dodge )

Western Sydney, who suffered that historic loss two years ago, scored a dramatic 3-2 comeback win on Tuesday night over Wellington.

A double on debut from teenager Lachlan Scott ensured a new-look Wanderers moved into the round of 16.

The Wanderers, whose most recent competitive match was last season's A-League grand final defeat, started poorly in wet and cold conditions at Campbelltown Stadium.

Hamish Watson and headline off-season signing Kostas Barbarouses put the Phoenix two goals to the good inside the opening half-hour.

The Phoenix created several other openings, but the home side dominated possession and were eventually rewarded as youth team graduate Scott netted either side of half time.

But it was Wanderers attacking midfielder Mitch Nichols who hit the goal of the match with a spectacular long-range winner midway through the second period.

Fellow A-League club Melbourne City avoided a potential banana skin with a hard-fought 2-1 away win over Floreat Athena in Perth.

Nick Fitzgerald put City in front with a sharp first-half strike and, although Floreat briefly drew level midway through the second half, Anthony Caceres restored the lead almost immediately for a worthy winner.

AAP