Martin Guptill smashed 93 not out from 30 balls as New Zealand thrashed Sri Lanka by 10 wickets in Christchurch to go 2-0 up in their one-day series.
The 29-year-old hit his country's fastest one-day international 50, reaching the milestone off 17 balls to beat Brendon McCullum's record of 18.
He fell short of AB de Villiers' world record of 16 but went on to hit eight sixes and seal victory in 8.2 overs.
Sri Lanka were bowled out for 117 from 27.4 overs earlier in the day.
"It was a superb innings. You can't describe it," said captain McCullum. "It's something you witness only once or twice in your life.
"There are very few guys in the world who can play like that."
The tourists opted to bat first but struggled almost from the off, with Matt Henry (4-33) and Mitchell McClenaghan (3-32) doing the main damage. Nuwan Kulasekara, batting at eight, was Sri Lanka's highest scorer with 19.
Guptill smashed the first ball he faced towards leg gully but, despite getting two hands on the ball, a diving Milinda Siriwardana could not prevent it going for four.
And Sri Lanka were made to pay a heavy price as the hosts cruised to their victory target.
Guptill was partnered by Tom Latham, who made 17 not out, as a back injury prevented McCullum from opening the batting.
The 34-year-old was injured when he collided with an advertising hoarding while diving to stop the ball.
McCullum, who announced last week that he would retire from international cricket in February, has had a long-standing back problem and will have it reassessed before Thursday's third game of the five-match series.