Sohail Tanvir was in good all-round form in Pakistan's win
Pakistan thrashed Hong Kong by 155 runs in Karachi and Bangladesh beat United Arab Emirates by 96 runs in Lahore on the first day of the Asia Cup.
Sohail Tanveer hit a 55-ball 59 and added a vital 100-run eighth-wicket stand with Fawad Alam (63 not out) to lift Pakistan from 161-7 to 288-9.
Tanveer then took 2-20 to bundle the qualifiers out for 133 in 37.2 overs.
Bangladesh scored 300-8 thanks to captain Mohammad Ashraful's 109 and dismissed their opponents for 204.
Only opener Arshad Ali (41) and Khurrum Ali (78) offered any resistance for the minnows.
Hong Kong's players were subsequently fined 5% of their match fee for a slow over-rate against Pakistan, with captain Tabarak Dar being fined 10%.
The International Cricket Council's code of conduct rules that players are fined 5% for every over their side fails to bowl in the allotted time, with the captain's fine doubled.
Four-time winner India - the other team in Group B - will meet Hong Kong on Wednesday before taking on Pakistan on Thursday.
Two teams from the group advance to the Super Four Stage, where they play three matches to decide the finalists, who will meet on 6 July.