The experience and leadership of Sydney captain Teresa Polias has been hailed by teammate Remy Siemsen heading into the W-League finals.

Polias scored a stunning free-kick in the mid-week showdown against Melbourne Victory, the Sky Blues snatching the premiers plate after the 2-1 win.

Young Matildas forward Siemsen says the 30-year-old Polias, in her 10th campaign with Sydney, looms as a crucial player in the semi-final against Canberra United on Monday - with a chance to host the grand final on the line.

"She gets better every single season, as well as every single week," Siemsen said.

"She's got a wealth of experience, and she's someone we're going to be looking to for encouragement and she's just going to be driving that force for us.

"She's someone that's just an absolute standout week-in and week-out."

Canberra head to Sydney having failed to score in their two clashes with the Sky Blues this season.

Sydney beat United 4-0 in February before the teams shared a goalless draw in the return fixture in Canberra in March.

Despite that record, Siemsen says the threat of W-League record goalscorer Michelle Heyman cannot be overlooked by the hosts.

The 32-year-old scored 10 goals in her return season after coming out of retirement and Siemsen knows stopping Heyman will go a long way to deciding the outcome on Monday.

"She's been a goalscoring machine all season and she's been a threat up top so we'll be trying to shut down those channels very quickly," Siemsen said.