The left-hander reached the milestone in just 14 balls, two deliveries more than Yuvraj Singh’s record fifty set at the 2007 World Twenty20, during a sensational innings.
Munro also broke the record for the Black Caps’ quickest T20 half-century, smashing the 19-ball effort that Martin Guptill had set just five overs earlier.
The 28-year-old blazed one four and a remarkable seven sixes, the last of which completed his fifty and victory, while skipper Kane Williamson was unbeaten on 32 off 21 deliveries.
But it was in-form Guptill who first provided the entertainment with six fours and five maximums in a brutal 25-ball 63 that blew Sri Lanka away.
Angelo Mathews led the way with the bat for Sri Lanka by contributing a career-best 81 not out to his side’s 142 for eight after losing the toss on a flat pitch.
Tillakaratne Dilshan was the only other touring batsman to reach double figures, hitting 28, while Grant Elliott returned 4-22 from four overs.
That proved no where near enough for the Black Caps, without Brendon McCullum, as they proved their World T20 credentials by racing to victory with half their innings remaining courtesy of Guptill and Munro’s brutal hitting.