The Sky Blues have been in a battle with Western Sydney to avoid a first-ever wooden spoon for the club, and Panama international Riley Tanner grabbed two decisive goals at Leichhardt Oval to propel Sydney (18) two points above the Wanderers.
Earlier on Saturday, forward Kelli Brown kept Newcastle's slim finals hopes flickering, producing one of her best games of the season to guide the Jets to a 3-1 win over Adelaide United.
Knowing only a victory would keep their post-season hopes alive, Brown bagged a double at Adelaide's ServiceFM Stadium.
The win moves Newcastle (23) within three points of the sixth-placed Central Coast Mariners (26), but they will need to beat ladder-leaders Melbourne City next Sunday and have other results go their way to progress.
One of those results was a seventh-placed Victory (25 points) loss, whose hopes of making the finals will rest on their crucial last-round clash with Perth Glory next Friday.
Melbourne drew first blood on Saturday when Rachel Lowe received the ball on the edge of the box and hammered it into the top left corner.
But Tanner equalised when she intercepted a lazy pass, stormed down the field, and slotted the ball past Victory's keeper Courtney Newbon in the 31st minute.
After halftime, Tanner found a similar goal when she picked off a subpar pass from Victory captain Kayla Morrison before striking it into the back of the net.
15-year-old Willa Pearson appeared to concede a handball for Sydney in the dying minutes, but the referee didn't pick it up, and the home side emerged victorious.
Adelaide will rue their loss as they missed out on jumping into the treasured second spot.
Instead, they will stay fourth (30), one point behind second-placed Wellington (31), with both the Phoenix and third-placed Canberra United (30) yet to play in the competition's second-last round.
Adelaide never led in front of their home fans after Brown converted in the 23rd and 83rd minutes.
Josie Allan also scored for Newcastle when midfielder Sophie Hoban wrestled down the right edge and cut the ball back to the 19-year-old, who guided it into the bottom left corner.
Adelaide did have a moment of celebration when Chelsie Dawber curled the ball onto the head of captain Isabel Hodgson, who scored in the 41st minute.
