Riley McGree scored a hat-trick on Saturday night at Central Coast Stadium and Roy O'Donovan netted a double. The second-placed Jets dominated, coming into the final-round match off three-consecutive losses and two goalless efforts.

Newcastle led 3-0 inside 24 minutes through goals to Joey Champness (10th minute), O'Donovan (20th) and McGree (24th).

Champness finished from a McGree ball, Steve Ugarkovic put O'Donovan away on goal and McGree did it all himself with a strike from the edge of the box.

The Jets were in control until Andrew Hoole's deflected cutback fell to Connor Pain, who scored in the 39th minute for the hosts.

The Mariners, in last place after Wellington upset Melbourne City 2-1 earlier on Saturday, peppered the Jets' goal late in the half without success.

Newcastle, who will host a grand-final qualifier on April 27, lost centre-back Ben Kantarovski to a hamstring injury just before halftime.

The Jets quickly snuffed out any hope of a Mariners comeback when McGree scored with another left-foot strike in the 53rd minute. Lachlan Jackson, who came on for Kantarovski, made it 5-1 with a free header off a Dimi Petratos corner in the 61st minute.

Champness was fouled by Jake McGing and O'Donovan converted from the spot in the 67th minute and McGree struck again eight minutes later. Trent Buhagiar pulled one back for Central Coast in the 80th but Petratos made it 8-2 a minute later.

It is just the second time a side have scored eight goals in an A-League match.

The thrashing marred the farewell of retiring Mariners stalwart Josh Rose, who was substituted in the 72nd minute to a standing ovation.

Jets coach Ernie Merrick was pleased to see his changes to the starting side work and Newcastle show no mercy in the second half.

"I think it was just getting the right people in the right positions, and just tweaking that so the position they were playing was suiting their skills," Merrick said.

"And they were certainly up for it, the boys. You could see it as soon as they came out.

"My message at halftime was do not sit on a 3-1 win and just defend it.

"It doesn't work in finals - it never works. So you've got to go out and see if you can score more goals and put them under more pressure and they did that very well."

Interim Mariners coach Wayne O'Sullivan, set to hand over to new boss Mike Mulvey, said the loss "really hurts", especially given Rose's farewell and with the wooden spoon on the line.

It was the worst home loss for any club in A-League history.

"We're hurting as much as the fans are," O'Sullivan said.

"I'm an inaugural Mariner, so no one hurts more than me. You cut me and I bleed yellow and blue.

"I say sorry, and say we'll put it right."

Australian Associated Press