The Dragons were pushed all the way by the Roosters in the first standalone NRL Women's match in Australia, however they held firm to secure a 24-16 victory.

Jessica Sergis was the hero for the Dragons, the centre putting her team in front with an intercept try in the 35^th minute.

The try was her second of the match, the 22-year-old turning a one-on-one strip into a runaway try in the first half.

St George Illawarra will now play defending champions Brisbane in next Sunday's decider at ANZ Stadium.

Like they were in last week's win over the Warriors, the Dragons were slow out of the blocks and it was the Roosters who opened the scoring on Sunday afternoon.

St George Illawarra hit back almost immediately through a superb individual effort from Jessica Sergis, however it didn't take long for the Roosters to regain the ascendancy.

Sydney were able to convert the momentum into points, with Bobbi Law crossing in the 18th minute to put her team in front.

With the Dragons needing a victory to progress to next week's grand final and the Roosters on top, the final 10 minutes of the opening half were shaping as a crucial period.

St George Illawarra were able to fight back and eventually the momentum swung back in their favour.

Suddenly, the Dragons attack clicked into gear, with a long shift to the left allowing Tiana Penitani to break free and level the scores.

Just moments later St George Illawarra were in again, Shakiah Tungai finishing off a crisp attacking move in the right corner to put her team back in front.

The half-time break came at the worst possible time for the Dragons, with the Roosters able to reset before coming out for the second 30.

It didn't take long for Sydney to level the scores, with the retiring Ruan Sims charging over from close range.

The Roosters rolled forward into attacking field position from the ensuing kickoff, however, for the second time in the match, Sergis swung momentum back in her team's favour.

The centre took an intercept and raced 80 metres to put the Dragons back in the lead 22-16.

St George Illawarra spent much of the remainder of the match searching for the knockout punch and it ultimately came in the 56^th minute when halfback Maddie Studdon landed a penalty goal to kick her side eight points clear and secure the victory.