Tamim Iqbal and Mushfiqur Rahim struck superb centuries as Bangladesh recorded only their second one-day international victory over Pakistan in Mirpur on Friday.
The pair shared a third-wicket stand of 178 to help Bangladesh to a highly competitive total of 329-6, a target that was too much for Pakistan.
Captain Azhar Ali (72) gave the tourists a solid start to build from, but they lost six wickets for 33 runs as Pakistan fell to a 79-run defeat.
Pakistan's new-look side – without the retired Misbah-ul-Haq and Shahid Afridi – made a promising start with two wickets inside the opening 20 overs, while restricting the hosts to just 67 runs.
However, with Tamim and Mushfiqur at the crease, Bangladesh soon took control, the former leading the charge with 92 in the partnership.
Showing particular strength on the off-side, Tamim struck 15 fours and three sixes in his 132, while Mushfiqur became Wahab Riaz's fourth wicket (4-59) having reached 106.
Wahab was the shining light in a poor bowling display that saw Saeed Ajmal make a terrible comeback to international cricket, the spinner returning career-worst figures of 0-74 after his suspension for an illegal action was lifted.
Facing the prospect of chasing down Bangladesh's highest ODI score, Pakistan started promisingly with an opening partnership of 53 between Azhar and Sarfraz Ahmed (24).
Haris Sohail (51) and Mohammad Rizwan (67) provided more fire-power in the middle order as Bangladesh began to get nervy, but Pakistan's good work was undone by a terrible six-over spell.
Pakistan's collapse began with the dismissal of Fawad Alam (14) by Arafat Sunny (3-47) and, after another four wickets had fallen, it was left to captain Shakib to secure the win.
He trapped Ajmal lbw for a duck to complete a momentous win for Bangladesh - their first in 16 years against Pakistan - and give them a 1-0 lead in the three-match series.