Lancashire Thunder 137 for 6 (Jones 69, Farrant 3-24) beat Southern Vipers 133 for 9 (Bates 40, Lamb 4-17) by four runs
England left-arm seamer Tash Farrant claimed only the second Kia Super League hat-trick, but it wasn't enough for the Southern Vipers to secure victory over a buoyant Lancashire Thunder at Liverpool.
Last season's finalists have now lost their last two games as, like the Thunder in their 137 for 6, they stumbled late on pursuing 138.
Farrant's trio was central to the Thunder's loss of four wickets in eight balls without addition in the 18th and 19th overs as they slipped from 123 for 2.
Vipers captain Suzie Bates top-scored with 40, but the visitors slipped from 104 for 2 in the 16th and failed to chase 14 off the last, with offspinner Emma Lamb starring with four late wickets in a four-run win.
The Vipers had started their chase without Tammy Beaumont after she failed a concussion test following a blow to the head whilst behind the stumps in the first innings - thought to be when Eve Jones scooped Bates in the 15th over.
After Amy Satterthwaite fell to Arran Brindle, Farrant had Jones caught at midwicket by Mignon du Preez with the third ball of the 19th over before Sophie Ecclestone holed out to Bates at long-on.
Lamb then skewed to Katie George at point off 22-year-old Farrant, who has played five T20 internationals this year. Yorkshire's Katherine Brunt took the first hat-trick in 2016 - also against Lancashire.
After play was delayed by an hour and the Vipers had elected to bowl, Lancashire paced their innings well to get into position to launch in the last three overs, with opener Jones leading the way with 69 off 65 balls.
She posted the Thunder's highest score in KSL history and shared 64 inside eight overs for the third wicket with Satterthwaite to advance from 59 for 2 after 10 overs on a green looking but true pitch.
Jones reached 50 off 48 balls in the 14th over for the Thunder, who won only their second ever KSL game by beating Yorkshire Diamonds on Friday.
And their total was only just enough to see off the 2016 champions, who were beaten in the final by Western Storm last year and have now lost two of their three matches this season.
The visitors were allowed to replace Beaumont with Paige Scholfield as a concussion replacement.
Bates and Danni Wyatt took their side to 43 without loss after six overs of Powerplay and shared 56 inside eight before Wyatt was lbw to Danni Hazell's offspin.
Alex Hartley then had du Preez superbly caught at deep midwicket by Nicole Bolton before Bates, who waited 30 balls for her first boundary, fell to another spinner Ecclestone at 104 for 3 in the 16th.
When Lamb had Brindle caught at mid-on and Amelia Kerr caught at long-off in the 17th - a double wicket maiden - the Vipers fell to 107 for 5 to heighten tensions.
Ecclestone bowled Farrant and had Sara McGlashan stumped in the penultimate to leave Lamb defending 14 off the last over. And she had Scholfield and Fi Morris, needing five off the last ball, caught on the way to the Thunder's best figures - 4 for 17.