Western United have taken a big step towards securing a maiden A-League finals berth, knocking Western Sydney out of contention with a thrilling 5-3 win at Kogarah’s Jubilee Oval.

United stretched out to a 3-0 lead through Josh Risdon, Besart Berisha and Alessandro Diamanti, before Western Sydney pegged it back to 3-3 through Mitch Duke’s brace and a goal to Tass Mourdoukoutas.

But late goals to Max Burgess and Diamanti put down Western Sydney’s late resistance and spared United’s blushes.

In teeming rain, United seized control in the seventh minute when Burgess whipped a left-footed cross into the six-yard box, where an inexplicably unmarked Risdon headed home.

In the 19th minute, Risdon helped double United’s lead.

Diamanti slipped a ball through for the fullback, who skidded a delightful cross past the Wanderers’ defence for a surging Berisha to dispatch his 16th goal of the season.

United thought they had sealed the deal through Diamanti’s spectacular 52nd-minute effort.

The Italian played a short corner, received the ball back and lofted a left-footed chip over goalkeeper Tristan Prendergast.

An unmarked Duke kicked off Western Sydney’s unlikely resurgence in the 69th minute, heading home Bruce Kamau’s looping cross.

Then, Mourdoukoutas latched onto Pirmin Schwegler’s free kick with a delightful backheel to make it 3-2 in the 76th.

Six minutes later Duke volleyed home to level the scores and seemingly put the Wanderers in the box seat for an unlikely win.

The weather made for a wet and wild night in Kogarah. Photo: ABC News/Brendan Esposito

But those hopes were extinguished when Burgess caught Mourdoukoutas dallying on the ball, pinched it and ran on to restore the lead in the 84th minute.

Three minutes later Diamanti secured the points with a second classy chip.

United, playing in their first season, closed the gap to sixth-placed Adelaide to two points with three games remaining.

-AAP