England captain Heather Knight made 97 as Western Storm began their Kia Super League title defence with a seven-wicket victory over Yorkshire Diamonds.
Lauren Winfield (41) and Australia's Delissa Kimmince (55 not out) helped Diamonds set 162-5 from their 20 overs.
Storm lost Rachel Priest to the first ball of their reply but India opener Smriti Mandhana (48) and Knight took them to 166-3 and a bonus-point win.
Loughborough Lightning and 2017 runners-up Southern Vipers also won.
England wicketkeeper-batter Tammy Beaumont scored 61 off 44 balls against old club Surrey Stars as Vipers made 145-3 to triumph with three overs to spare.
Sophia Dunkley's 66 helped Stars recover from 18-4 to post 141-9 at Guildford, with bowlers Fi Morris (4-22) and Tash Farrant (3-16) impressing for Vipers.
Meanwhile, Lancashire Thunder, who failed to win in the KSL last year, were bowled out for just 72 as they lost by six wickets to Lightning at Southport.
Sophie Devine (3-15) and Jenny Gunn (3-10) stood out with the ball for Loughborough, Georgia Adams top-scoring with 22 as they reached 74-4 off 15.1 overs.
The six teams will play 10 group matches in 2018, instead of five as in the first two years of the competition.