Harshal dismissed Hardik, Pollard and Chahar to bag three in three; Glenn Maxwell, Yuzvendra Chahal and Virat Kohli also fire for RCB.
With 24 required from ten balls, he smashed Prasidh Krishna for 20 runs in four balls.
Punjab Kings defend 125 to keep their hopes of making the top four alive.
Against Rajasthan Royals, Nortje, Rabada and Avesh helped Delhi defend their third-lowest total in IPL.
Devdutt Padikkal and Virat Kohli fifties goes vain as Chennai Super Kings won six wickets at Sharjah on Friday.
Tripathi and Iyer scored fifties in KKR seven-wicket win. MI slip to sixth spot in the standings.