After picking three wickets, Hayley Matthews completed a fine all-round show by scoring a 38-ball 77, while Nat Sciver-Brunt made 55 off 29 balls.
Earlier, RCB were all out for 155 in 18.4 overs
Opting to bat after winning the toss, RCB were off to a brisk start with the opening duo of skipper Smriti Mandhana and Sophie Devine adding 39 runs in 4.2 overs, when the latter was dismissed by Saika Ishaque for an 11-ball 16.
Disha Kasat failed to open her account, before Mandhana was sent back by Hayley Matthews for a 17-ball 23, the RCB captain yet again falling after getting a start.
Richa Ghosh, then, contributed 28 off 26 balls. Later, RCB were helped by useful cameos from Kanika Ahuja (22 off 13), Shreyanka Patil (23 off 15) and Megan Schutt (20 off 14).
Brief scores: Royal Challengers Bangalore: 155 all out in 18.4 overs (Richa Ghosh 28; Hayley Matthews 3/28).
Mumbai Indians: 159/1 in 14.2 overs (Hayley Matthews 77 not out, Nat Sciver-Brunt 55 not out).
