You need to re-evaluate your statement. You strongest team WEST INDIES is out of the U19 World cup and its the NZ team which progressed further. WI was not able to finish the game and took the match easy in the last 5 overs which caused them the match.
When I made the post, it looked as if West Indies would win easily. And it looks like they got choked during the final overs. At one point, New Zealand were struggling at 8/153. They needed another 86 runs to win. Who would have thought that West Indies would lose from this point? The partnership between Joey Field and Kristian Clarke took the Kiwis to the semi-finals (where they will face a weak Bangladesh) and now West Indies can blame themselves for the missed opportunity.
Till the 48th over, I still believed that WI will win the match but NZ win was more than a miracle. If West Indies could get one more wicket, they could have got the match but unfortunately they were unable to get any wickets in the last 5 overs.