Western Storm 185 for 4 (Knight 76, Taylor 51*, Mandhana 49) beat Lancashire Thunder 109 (Nicholas 3-11) by 76 runs
Western Storm captain Heather Knight led by example as the defending Kia Super League champions defeated Lancashire Thunder by 76 runs at Taunton to qualify for finals day.
Knight top-scored with 76 and shared in stands of 66 and 102 for the second and third wickets with Smriti Mandhana and Stafanie Taylor respectively as the hosts posted an imposing 185 for 4 after being put in.
Unable to recover from the loss of early wickets, Thunder subsided to 109 all out in 18.2 overs as Storm secured a fifth successive victory to move clear of Loughborough Lightning at the top of the table. Wales international Claire Nicholas proved the pick of the bowlers, claiming 3 for 11 from three overs.
Coming into this game as the competition's leading run scorer with 338 at an average of 85, Mandhana carried on where she left off against Yorkshire Diamonds earlier in the week.
Far from being fazed by the early departure of opening partner Rachel Priest, pinned lbw by Sophie Ecclestone in the first over, Mandhana seized the initiative by trading almost exclusively in boundaries during a Powerplay that yielded 51 runs.
Off the mark with a cut four behind square, she plundered 14 runs from one Kate Cross over as she moved through the gears.
Thunder deployed four spinners in an attempt to limit the scoring while the fielding restrictions were in place, but Mandhana was quite prepared to go the aerial route, harvesting seven fours and two sixes and dominating a stand of 66 in seven overs for the second wicket with Knight.
Having hoisted Natalie Brown over long-on for the first six of the match, she repeated the feat at the expense of Alex Hartley in the eighth over, her 21st six of the tournament taking her to within one run of a half century.
No doubt intent upon realising three figures against Thunder for the second time in the space of seven days, Mandhana surprisingly surrendered her wicket cheaply next ball, persuaded by Hartley to hole out to Amy Satterthwaite at deep midwicket.
Charged with the task of building upon solid foundations, Knight and Taylor deployed deft placement and quick running between the wickets to advance the score to 86 for 2 at halfway.
Knight smashed a short-pitched delivery from Cross to the midwicket boundary for six to raise the 50 partnership in the 15th over and went to a 36-ball half century with her fifth four shortly afterwards.
Knight eventually slogged Cross to wide long-on in the penultimate over, but only after staging a hundred partnership with Taylor.
Prepared to play second fiddle while her captain was at large, Taylor hit out at the death to raise 50 in the grand manner with a huge six over midwicket at the expense of Ecclestone, the West Indian international finishing unbeaten on 51 from 37 balls.
Offspinner Nicholas clean bowled Evelyn Jones in the second over and then had the dangerous Satterthwaite smartly stumped by Priest off a wide delivery as Storm restricted their opponents to 37 for 2 in the Powerplay.
Freya Davies adhered admirably to the tenets of line and length to build scoreboard pressure from the River End, and Knight took full advantage by removing Nicole Bolton lbw as Thunder lurched to 38 for 3 in the seventh over.
When Indian batsman Hermanpreet Kaur was stumped by Priest off the bowling of Taylor for eight, the visitors were 43 for 4 in the eighth over and the game was effectively up.
Taylor then accounted for Emma Lamb in returning impressive figures of 2 for 18 from three overs, while Nicholas returned to remove Eleanor Threlkeld, who at least summoned a degree of resistance in posting 33 at a run-a-ball.