The veteran Australian Test star, who's been flying since his return from injury two-and-a-half weeks ago, blasted through Delhi's top-order, taking two wickets with his first two balls and a third in his following over in Monday's clash.
With Kumar also taking three wickets in his opening two overs after RCB had asked Delhi to bat, the pair left the Capitals reeling at an extraordinary 6-8, looking in danger of recording the lowest IPL total ever (RCB's 49 against Kolkata in 2017).
Only resistance from Abishek Porel (30) and David Miller (19) enabled Delhi to avoid that fate as they limped to 75, but in the 17th over, Hazlewood returned ruthlessly to finish the job, yorking Porel for his best IPL figures of 4-12 off 3.3 overs.
Kumar was just as good, taking 3-5 off his three as the pair left Delhi 6-13 at the end of the first six powerplay overs with their irresistible mix of swing, seam and the occasional hostile short one.
But once RCB had cruised to 1-77 for a nine-wicket win in 6.3 overs, with Virat Kohli (23no) becoming the first man to pass 9000 IPL runs -- no-one else has even gone past 8000 -- Hazlewood was judged to have edged it as player of the match.
Rightly so. He got danger man KL Rahul, fresh from scoring 152no in his last knock, with his short, sharp first ball that climbed on the Indian Test batter and forced him to rush his pull shot, so he steepled it up for a simple catch to wicketkeeper Jitesh Sharma.
Next ball, he had Sameer Rizvi caught behind, and in his following over, served up a vicious, rearing snorter that looped up off Nitish Rana's gloves.
"Those guys are so good with the new ball," sighed teammate Devdutt Padikkal, who eased RCB to the winning line alongside Kohli with 34no off 13 balls.
"In the slips, I'm expecting a catch every ball, and that's not something you'd say in a T20, but when those two are bowling, every ball is an opportunity."
Hazlewood loved every minute of this rare bowler's day in the IPL sun. "Probably turning up here after 500-plus runs in the last game, you don't expect that," he smiled wryly.
He only had one regret. That he wasn't allowed to bowl a fourth-straight over after his sensational first 18 balls.
"It would have been nice to bowl four-straight and get off the field," he sighed, imagining he might have been able to be substituted and put his feet up.
