Papua New Guinea had won two of 28 matches in CWC League 2 before this week. They now have double that and are severly reducing the UAE's chances of qualifying directly to the World Cup Qualifier without having to go through the play-off.
After beating them by 131 runs on Tuesday, the teams met again today in Dubai, with the visitors choosing to bowl first after winning the toss.
Riley Hekure took 5-13 - the second best bowling performance for PNG in ODIs - as the home team were bowled out for just 97, Vriitya Aravind top scoring with 26.
Papua New Guinea lost five wickets in their reply but opener Tony Ura held firm, scoring an unbeaten 35 to help secure a five wicket win in 26.5 overs.
The UAE play Nepal tomorrow and need a win otherwise they face having to win all four games in the final CWC League 2 tri-series that starts in Nepal on Thursday.