He smashed four successive sixes on the way to a brutal 31 off 14 balls, before taking two wickets and a catch and completing a run-out as England comfortably defended a total of 184 for eight.
New Zealand’s Jacob Oram served up his own display of power hitting as he raced to a 30-ball half-century, but there was a general feeling that his efforts would have little impact on the outcome from the moment the hosts slipped to 70 for six.
He was the last man out in the final over as the Black Caps were bowled out for 152, giving the impressive Ryan Sidebottom figures of 3-16 and ensuring England remain unbeaten in three games on this tour.
Mascarenhas’ name may dominate the headlines, but England also owed much to Kevin Pietersen for setting a challenging total on a quick pitch at Eden Park.
Indeed, with the exception of the occasional lapse in the field, they produced a fine all-round performance that also featured useful contributions from Paul Collingwood, Owais Shah and Phil Mustard with the bat.
New Zealand enjoyed early success with the ball after winning the toss as Luke Wright fell in the second over.
A short delivery from Chris Martin jagged back into Wright, rapping him on the gloves as he advanced down the track and looping to wicketkeeper Brendon McCullum, who made good ground to his right to take a fine diving catch.
Mustard managed one cross-batted six off Kyle Mills in his 20 before pulling Martin to debutant Jesse Ryder at deep midwicket, and Ian Bell played second fiddle to Pietersen in a rapid third-wicket stand of 34 that was ended when the former was yorked by Oram.
Pietersen, who had signalled his intent with a cute leg-glance first ball, struck five further fours and a dismissive six – pulled off the front front at Martin’s expense – in an innings that thrilled an already excitable crowd.
But the introduction of spin did for Pietersen, who drilled Jeetan Patel low to Ross Taylor at short midwicket in his first over, and the regular fall of wickets continued as Ryder removed Shah with his second delivery.
Shah looked in fine touch as he flicked 19-year-old seamer Tim Southee – also making his debut – off his legs for four and six in successive overs, but he paid the price for aiming across the line when he was trapped lbw for 23 attempting to sweep.
Though Mascarenhas’ brutal assault on Patel – the final four balls of the 16th over were unceremoniously dispatched into the crowd at long-on – restored England’s momentum, he and Collingwood perished in the space of five balls.
Mascarenhas slashed Mills to a relieved Patel at third man and Collingwood, also stepping away to leg, was taken by Scott Styris at the third attempt for 26 to give Southee a maiden international wicket.
Mills’ slower ball did for Stuart Broad, but Sidebottom and Graeme Swann managed a boundary apiece in the final over as England enjoyed a late flurry.
New Zealand’s reply was undermined by their twice losing two wickets in the space three balls.Sidebottom made the early inroads, hurrying McCullum into a pull stroke and trapping Taylor leg before with one that nipped back off the seam.
Ryder reinforced the positive impression he made in the field – despite criticism from former New Zealand wicketkeeper Adam Parore that he is carrying a few too many pounds to play at the highest level – with a rapid 22 containing a handful of powerful drives.
But, two deliveries after Jamie How chipped Mascarenhas to long-on, Ryder was run out by Bell as he slipped attempting to regain his ground at the non-striker’s end, Styis having turned down a single.
Styris himself perished moments later – he played on swinging wildly at Mascarenhas – and when Peter Fulton was bowled trying to work Broad to leg, New Zealand’s fate was sealed.
The dismissals of Mills, who swept Swann to Anderson at deep square-leg, and Southee – taken at long-on by Mascarenhas in Collingwood’s first over – underlined England’s dominance.
This being Twenty20, an upset remained possible while Oram was at the crease, his blend of powerful leg-side heaves, glorious straight drives and deft reverse sweeps bringing him seven fours and two sixes in his 61 before he picked out Anderson at long off.