New Zealand 137-0 off 16.1 overs (M Guptill 73*, C Munro 58*) beat Sri Lanka 136ao off 29.2 overs (F Karunaratne 52*, M Henry 3-29, L Ferguson 3-22) by 10 wickets.
Dark horses New Zealand underlined their potential to stay the World Cup course with a crushing 10-wicket victory of Sri Lanka in Cardiff.
New Zealand’s dominance was so overwhelming that the action was all over by 2.48pm, with only 45.3 of the possible 100 overs bowled.
A second shortened contest, after the West Indies’ humbling of Pakistan on Friday, was probably the last thing that World Cup organisers wanted.
But New Zealand and Sri Lanka are clearly in different places right now, and another mismatch was always on the cards.
Sri Lanka, who have lost nine of their last 10 one-day international series and been plagued by internal problems, batted for only 29.2 overs in making 136 — their third-lowest World Cup score.
Martin Guptill (73 not out) and Colin Munro (58 not out) then produced a dismissive response as the openers combined clever placement and heavy hitting to reach their target in just 16.1 overs.
Sri Lanka’s only consolation — if it can be called that — saw captain Dimuth Karunaratne enter the World Cup record books.
Opener Karunaratne, who has taken over the captaincy after a four-year ODI exile, made an unbeaten 52. In doing so, he became only the second batsman in World Cup history to carry his bat through a completed innings.
The feat had previously been achieved by the West Indies' Ridley Jacobs, who made an unbeaten 49 against Australia at Old Trafford in 1999.
This was a day, though, that belonged to New Zealand from the moment Kane Williamson won the toss and sought to exploit a green-tinged Sophia Gardens surface and favourable early overhead conditions.
Tim Southee was not risked because of a nagging calf complaint, but New Zealand's strong seam team is just one of the reasons why they are genuine contenders to improve on their 2015 runners-up finish.
Matt Henry stepped in for Southee and took three for 29 in an opening seven-over burst, removing Kusal Perera and Kusal Mendis in successive balls, but missed out on becoming the first New Zealander to take a World Cup hat-trick.
Trent Boult, who has taken more wickets than any other seamer since the 2015 World Cup, charged in with a three-strong slip cordon holding their breath.
Boult, though, was not at his best. He did not need to be as Henry zipped the ball around to shake Sri Lanka’s fragile confidence further.
Lahiru Thirimanne fell upon review to the second ball of the innings, with Henry winning his lbw appeal as replays showed the ball to be pitching on leg stump.
Karunaratne was fortunate to survive on nine when he nearly chopped on. The ball brushed the stumps but the bails, not for the first time in this tournament, failed to come off the groove.
Sri Lanka’s luck, however, ran out as Henry ended Perera’s entertaining 24-ball 29 and Mendis fell first ball to a splendid low Guptill grab at second slip.
The procession continued as Dhanajaya de Silva fell lbw to Lockie Ferguson, while Angelo Matthews edged Colin de Grandhomme to wicketkeeper Tom Latham.
When Jeevan Mendis became Ferguson's second victim to a sharp Jimmy Neesham catch, Sri Lanka had lost five wickets for 14 runs in 44 balls and were in total disarray.
Thisara Perera’s muscular approach offered Sri Lanka some encouragement, with his 23-ball 27 allowing the solitary 50 partnership of the innings with Karunaratne.
But the innings quickly evaporated as Ferguson finished with three for 22 and Boult and Mitchell Santner ensured that every Black Caps bowler would finish with some reward.
