Green was tasked with bowling the third and fifth overs of the first innings powerplay and delivered almost immediately, inducing a thick top edge from South Africa wicketkeeper-opener Ryan Rickelton, Mumbai's top scorer of 2026 with 436 runs at 43.60.
Three deliveries later, number three Naman Dhir - coming into the game with four 40+ scores in his last eight innings - was on his way for a three-ball duck, caught behind following a successful review.
Green then sent down a tidy third over in the 15th over of the innings, conceding only six runs to finish with three-over figures of 3-23.
His damage upfront choked Mumbai of any early momentum, whilst a typically miserly 1-13 (4) from West Indian veteran and KKR legend Sunil Narine ensured the men in blue were unable to recover to a winning score.
Green flicked South African fast bowler Corbin Bosch to fine leg for a score of just 4 in the run chase and watched on as India's Manish Pandey (45) and West Indian captain Rovman Powell (40) chipped away to complete the chase late in the 19th over.
KKR are in sixth place with one round to play, one point and Net Run Rate (NRR) behind fourth-place Rajasthan Royals.
They face Mitchell Starc's Delhi Capitals in their final game, whilst fifth placed Punjab Kings (Cooper Connolly and Marcus Stoinis) need to defeat last-place Lucknow Super Giants (Mitch Marsh and Josh Inglis) to keep their season alive.