People need to understand that this is the weakest Bangladesh under-19 squad ever since recently Nasir Hossain, Sohag Gazi, Mominul and Anamul Haque have left the system in the past 2 years and are succeeding for the senior team. Still Pakistan was 38/4 and likely would've lost since another 100+ runs were required with only 6 wickets left (half of them tail-enders).
Don't forget the Bangladesh senior team itself is already the youngest and Shakib, Tamim, Rahim etc are not only still young but heavily experienced whereas the Pakistan team is still old and young players are nowhere near experienced as them. Very likely Bangladesh official team in the near future will surpass Pakistan.