Spin from both ends as Mitchell Santner comes into the attack. The first ball is halfway down as Nigam pulls it over midwicket for a four and then takes one to race to 20 from seven balls.
Rizvi has struggled to get going as he plays two dots in a row before taking one to long-off.
Nigam, on 20, gets a lifeline as he slices the spinner uppishly behind point but fails to get it in the gap. However, Rohit at short thirdman puts down a simple catch.
DC are struggling on 49/3 in six overs, with Nigam getting them back with his attacking approach.
They will have to contend with Bumrah's four overs in the middle overs.