Knight holed out with two runs required looking to seal her century and victory with a boundary, before Stafanie Taylor (12no) hit the winning runs as Storm topped Diamonds’ 162-5 with 27 balls to spare.
Knight, dropped on 29 and caught off a no-ball on height grounds from Beth Langston on 56, was aiming to become the third woman to score a KSL century after New Zealand’s Rachel Priest and Suzie Bates reached three figures last season for Storm and Southern Vipers respectively.
The 27-year-old struck 13 fours and five sixes in her knock, putting on 80 with India’s Smriti Mandhana (40 off 28) for the second wicket after Priest was pinned lbw by leg-spinner Helen Fenby first ball and then dominating an 81-run alliance with Windies’ Taylor for the third.
Storm seamer Freya Davies had earlier claimed 2-28, with Australian Delissa Kimmince top-scoring for Diamonds with 55 not out from 41 balls and captain Lauren Winfield striking 41 from 29 up top.
Elsewhere on day one in the KSL, Vipers eased past Surrey Stars by seven wickets, while Loughborough Lightning skittled Lancashire Thunder for 72 en route to a six-wicket success.
Stars slipped to 18-4 after being inserted by Vipers at Guildford – openers Lizelle Lee and Bryony Smith dismissed for ducks – before Sophia Dunkley (66 off 43) hit 10 fours and a six to lift her side to 141-9.
Marizanne Kapp removed Vipers openers Danni Wyatt (6) and Bates (9) cheaply but former Stars player Tammy Beaumont (62no from 45) and Mignon du Preez (48) ensured the visitors won with 18 balls in reserve.
Thunder, meanwhile, lasted just 16.5 overs in Southport – Jenny Gunn (3-10) and Sophie Devine (3-15) doing the brunt of the damage as only opener Evelyn Jones (19) and tailenders Kate Cross (13no) and Natalie Brown (13) made double figures for Lancashire.
Lightning looked in slight danger at 35-4 with spinner Alex Hartley striking twice, but Georgia Elwiss (19no) and Georgia Adams (22no) kept their cool as the visitors won in 15.1 overs.
Lightning are live on Sky Sports Cricket from 6.55pm on Wednesday as they travel to the Ageas Bowl to play Vipers. Make sure you join us then!