Mitchell Duke scored either side of half-time to help put Western Sydney Wanderers within three points of A-League pacesetters Central Coast Mariners thanks to a 3-0 win over Perth Glory.

For a while it was proving to be a frustrating day for the hosts, having had two first-half goals ruled out by VAR, but they finally made the breakthrough on the stroke of half-time.

James Troisi did well to turn out of danger in the penalty area before clipping an inviting cross into the danger zone for Duke to nod home.

The second half was 78 seconds old when Duke got his second, latching on to a long ball over the defence by Keanu Baccus and holding his nerve with an emphatic finish after shrugging off a defender.

Three minutes later it was game over for the Glory, as Bernie Ibini led a rapid break and fed Troisi to his right with the goalkeeper rushing out, leaving the forward with the simplest of finishes.

Victory puts Wanderers three points off the top and another three clear of Adelaide United in third, though both teams have at least one game in hand on Western Sydney.

The Glory are now winless in four A-League games and face a real fight to secure a spot in the Finals.