Sydney FC's record plummeted to just one win in their last eight games as a brace from Nathan Burns gave Wellington Phoenix a 2-0 victory at the Allianz Stadium.
Sydney came close to opening the scoring when Shane Smeltz met Bernie Ibini-Isei's left-wing cross on 25 minutes, but he could only stab the ball high and wide of goal.
Five minutes later, Marc Janko fired against the bar from just six yards out after Glen Moss had saved Smeltz's goalbound effort from point-blank range, as the home side again went close to breaking the deadlock.
The in-form Burns then put Wellington ahead midway through the second half with his fifth goal in four matches.
Burns collected the ball wide on the Wellington left, before cutting inside and beating two Sydney defenders to fire beyond Vedran Janjetovic at the near post.
The striker then grabbed his second of the game when he collected Roy Krishna's flicked pass and fired into the far corner from inside the Sydney box.
Sydney had a late shout for a penalty waved away when Smeltz appeared to be pulled down in the box, but did little to threaten an otherwise comfortable Wellington side.
The result sees Wellington leapfrog Sydney into fourth place in the A-League, with Graham Arnold's side falling to fifth.
