The Eagles, who suffered a three-wicket loss to Northern Districts, had already locked in their place on top, regardless of Round 10 results.
Caitlin Edmunds top-scored with 21 for West Torrens, but the team managed just 7/96 after 20 overs.
The Jets responded with 7/99, reaching the total in the final over, largely thanks to Tabatha Saville’s quick-fire 31 from 26 balls.
Requiring a convincing win for a top-two finish, the Jets fell short and had to settle for third place on the table.
Amelia Rault top-scored with the bat for Sturt, compiling 36 runs and getting the Blues to 5/88.
Sparked by Stacey Oates (2/10), Kensington suffered a crushing top-order batting collapse, losing 4/1.
Bella Smith and Shania McKinnon both made 21 runs for Kensington, with Smith also taking 2/18, but the Browns still fell 12 runs shy of victory.
Southern District captain Jess O’Reilly took 3/10 in her side’s eight-wicket thrashing of Port Adelaide, bowling the Magpies out for a miserly 40 runs.
Kelly Armstrong’s 21 not out helped secure the win for the Stingrays in just 7.2 overs.
The final between West Torrens and Kensington will take place on Saturday 16 February at Karen Rolton Oval from 10:30am.