Sydney FC's formidable derby record against Western Sydney Wanderers continued after classily accounting for their rivals 2-0 in Saturday's Westfield W-League contest at Stadium Australia.
Mackenzie Hawkesby's first half penalty gave Ante Juric's side the lead at half time before Ellie Brush gave the Sky Blues breathing room by volleying Teresa Polias' corner home midway through the second.
The result is Sydney's second victory over the Wanderers in just over a fortnight, having eclipsed the Red and Black 3-0 in their Round 1 clash.
Dean Heffernan's side turned in a much-improved performance but could not match Sydney's quality on the day.
Sydney move to the top of the Westfield W-League ladder and have now won 15 of 18 Sydney derbies.
The two sides traded early blows as Brush headed Polias' corner over, and Wanderers midfielder Liv Price curled an effort wide of Jada Whyman's post after a neat turn and run from midfield.
Sydney began to gain a foothold through the pace of Siemsen, Ibini and Cortnee Vine. And it was Ibini - who scored a brace in Sydney's Round 1 win - drew a penalty after going down under the challenge of Danika Matos.
Hawkesby buried the penalty to give Juric's side a 1-0 lead after 30 minutes, and Sky Blues fans were soon left wondering how they did not double that advantage when Siemsen and Hawkesby hit the post and crossbar respectively in quick succession.
Former Manly United gun Siemsen had not scored in eight matches prior to kick off and that drought continued when she pulled an effort uncharacteristically wide when put through one on one with Wanderers goalkeeper Courtney Newbon.
Sydney continued to push on in the second half and Siemsen was thwarted by a remarkable acrobatic clearance from Nikola Orgill.
However, the Wanderers fell to an unassailable deficit when Brush reacted quickest to volley back in off the crossbar following Polias' corner.