In oppressive, hot and humid conditions in the WA capital, the Sky Blues proved too good for a lethargic Glory side that at times appeared to be going through the motions as a disappointing season that once promised so much draws to a close.

Sydney, though, still has it all to play for as goals to Nicky Carle and Bruno Cazarine in each half gave them a comfortable win.

The result still sees Sydney sitting in ninth on the Hyundai A-League table, but they now have 29 points and are just four points adrift of sixth-placed Melbourne Heart with three games remaining for the Sky Blues and just two for Heart.

In what should set up a thrilling finish to the regular season, Sydney, unbeaten in 2011 so far, play the three teams they are competing against for a finals position in Wellington, Newcastle and Heart in their last three matches.

From the outset the visitors played like a team with plenty on the line as they launched a series of corners at the Glory defence.

But it wasn't a set-piece that delivered the opening goal but some sublime passing between Cazarine and Carle in the ninth minute.

As Sydney worked their way forward along the left flank, Carle was left unmarked in the middle of the park 40 metres from goal as he received the ball from Scott Jamieson.

Darting forward, Carle and Cazarine produced two one-twos in succession. But the second time Cazarine took the ball, he brilliantly volleyed it up for Carle to nod into the back of the net, his header looping over Tando Velaphi, who'd come marginally off his line.

It was largely uneventful for the rest of the half as neither side created many clear-cut chances, but it was the Sky Blues that came out after half-time with more vigour as they doubled the advantage through Cazarine in the 53rd minute.

Sung-Hwan Byun sent in a long ball over the defence to Dimitri Petratos, whose intelligent flick on was converted by Cazarine, who slid the ball under a diving Velaphi from close-range.

The goal seemed to spark the hosts as they responded through a series of attacks for the last half hour. But Mile Sterjovski still sent a one-on-one with Ivan Necevski wide of goal as Sydney ran out comfortable winners.

Perth Glory 0
Sydney FC 2 (Carle 9', Cazarine 54')
Crowd; 5576 @ nib Stadium