Harshal, who dropped the catch in the previous over, comes into the attack to bowl the sixth over.
Patidar flicks the second ball over midwicket for a four and guides the next past short thirdman for another boundary.
Two balls later, he hammers an overpitched delivery for the third boundary of the over before Harshal gets some away movement to beat right-hander Patidar.
RCB reach 56/2 in six overs, with Punjab ruing three dropped catches in the Powerplay.
Kohli has not imposed himself, as he was put down twice, to score 22 from 14 balls, while Patidar is on 13.