The Jets will take on fourth-placed Sturt in the semi-finals this weekend, while second-placed Kensington will tackle Southern District.
Round 10 saw the Jets clinch a tight win over Kensington in a low-scoring game where 19 wickets fell.
The Browns were dismissed for just 74 in under 31 overs, with Rachel Church (21) and Shae Daly (23 not out) making the most impact with the bat.
In reply, it was Neisha Iles (21 not out) who top-scored, seeing the Jets through to the required total, with just one wicket in hand in the 33rd over.
Browns captain Sarah Lowe collected brilliant figures of 4/18 from 10 overs.
Southern District dominated Sturt posting a monster score of 6/224, thanks to Kelly Armstrong (87) and Hannah Sampson (44).
Stacey Oates (3/30) dismissed the top three batters but was unable to restrain the Stingrays much further.
Sturt’s Emma de Broughe compiled a mature 74 from 128 balls, but it was only Oates (10) who was able to join her on double figures.
The Blues let poor communication get the better of them, with five run outs in the middle.
Sturt batted through to the 46th over, where the final wicket fell, the Stingrays having them all out for 140.
Port Adelaide forfeited against West Torrens, however neither team were mathematically able to move into a top four position.