Last season's wooden spooners Newcastle Jets are the surprise unbeaten leaders of Australia's A-League after champions Sydney FC's upset loss this weekend.

The Jets, under former championship-winning coach Ernie Merrick, downed Adelaide United 2-1 in Adelaide to stay undefeated after six rounds.

Newcastle took full advantage of Sydney's stunning 2-0 loss to the Central Coast Mariners in Gosford for their first defeat in nine months to lead the Sky Blues by one point.

Nikola Mileusnic put the Reds ahead in the 24th minute but goals from Ben Kantarovski and Andrew Nabbout clinched all the points for the rejuvenated Jets.

Merrick said he drew similarities between the Jets' current opening and that of his 2006-2007 Melbourne Victory side, who won their first seven matches before going on to claim the championship.

Sydney FC reject Andrew Hoole and the Mariners denied former coach Graham Arnold his 100th A-League win in a major upset over the reigning champions.

Goals from Hoole and Jake McGing gave Paul Okon's Mariners their first win of the season after three draws and two defeats.

Scottish striker Ross McCormack earned Melbourne City a 1-1 draw with Western Sydney Wanderers and third spot with a late penalty cancelling out Jaushua Sotirio's opener in Melbourne on Sunday.

A late equaliser from former Socceroo Brett Holman earned Brisbane Roar a 1-1 draw with Melbourne Victory to extend Victory's winless start to the season.

Kevin Muscat's men looked to have done enough when Besart Berisha scored on his return from suspension in the 79th minute before substitute Holman got on the end of a Jack Hingert cross to fire home.

Serbian striker Andrija Kaludjerovic grabbed a brace as Wellington Phoenix registered their first win of the season with a 5-2 victory over Perth in Wellington.

The win over fifth-placed Perth finally shifts Wellington off the bottom of the ladder into seventh place.