Sydney FC have upset favourites Brisbane Roar in a dramatic Westfield W-League semi-final 3-2 at the QSAC on Saturday.

The visitors showed plenty of tenacity to hold off a surging Roar late on, despite being a player down, after setting the platform for the win with a dynamic first-half display.

A cracking effort from Annalie Longo and a well-taken double from Sam Kerr proved enough for Sydney, while Brisbane's goals came from Emily Gielnik and Vedrana Popovic.

Sydney finished with 10 players as Emma Kete was red-carded with 13 minutes to go.

Sydney almost got off to a sensational start, as Kyah Simon lashed a shot just wide a few seconds into the match after Kerr had crossed from the left wing.

Somewhat against the run of play, Brisbane went ahead after 14 minutes.

Tamika Butt showed blistering pace to leave the Sydney defence in her tracks and get on the end of an optimistic long ball from Laura Alleway.

Unselfishly, she squared the ball to Gielnik who had an easy job to tap home the opening goal.

Longo was responsible for Sydney's stunning reply five minutes later, as she went to collect a short corner wide on the left, turned, and curled a sumptuous shot into the top right corner of the goal for a deserved equaliser.

Sydney's highly mobile attacking trio of Kerr, Simon and Kete were causing all kinds of problems for the Brisbane defence and Sydney took the lead after 29 minutes courtesy of Kerr.

She gathered on the left and, finding herself with plenty of space, drove in a low shot to put her side ahead 2-1.

The visitors went into the break with the lead after a dynamic first-half display.

The Roar started the second half with a more up-tempo approach, and Butt created the first clear-cut chance for herself after nine minutes when she robbed Liz Ralston of the ball near the left touch line and raced towards goal.

Her shot was smothered by Shamiran Khamis, however.

The unstoppable Kerr scored her second goal just after the hour mark to put Sydney well in command.

Kerr turned Roar defender Brooke Spence with ease before guiding another well-placed shot past the goalkeeper.

Just as the match seemed to be getting away from Brisbane, Butt and Popovic hauled their side back into the contest.

Butt's cross from the left was perfectly weighted and Popovic only had to get her head to it to beat Khamis.

There was plenty of drama still to come, as Brisbane threw everything at their opponents.

Kete was sensationally given a straight red card by referee Kirralee Gardener after 77 minutes for an off-the-ball incident.

Heroics from Sydney's teenage shot-stopper Khamis foiled Roar captain Clare Polkinghorne, whose header and subsequent shot were both brilliantly blocked.

Butt had one last chance to equalise for Brisbane, but her powerful shot from the edge of the area flew well over the crossbar to deny the big home crowd the goal they craved.

Sydney go through to play for the championship while Brisbane miss out on the final for the first time in Westfield W-League history.

Brisbane Roar 2 (Emily Gielnik 14, Vedrana Popovic 75)
Sydney FC 3 (Annalie Longo 19, Samantha Kerr 29, 61)

Brisbane Roar: 2. Laura Alleway, 4. Clare Polkinghorne (c), 5. Brooke Spence, 7. Erika Elze, 8. Elise Kellond-Knight, 11. Vedrana Popovic, 13. Tameka Butt,16. Sachiko Tatsuoka (6. Ashley Spina 45),17. Emily Gielnik (15. Hannah Beard 87), 18. Kate Stewart (gk) (Hoshima Kishi 45), 19. Katrina Gorry

Sydney FC: 2. Teresa Polias, 3. Elizabeth Ralston, 4. Samantha Kerr, 9. Caitlin Foord, 10. Renee Rollason (7. Nicola Bolger 74), 11. Annalie Longo, 14. Alanna Kennedy, 16. Ellyse Perry (12. Chloe Logarzo 85), 17. Kyah Simon (c), 19. Emma Kete, 20. Shamiran Khamis (gk)