Pakistan were cruising along nicely at 230-4 when West Indies grabbed four quick wickets to put Pakistan on the back foot at 255-8 by close of play at the Sharjah stadium.
At close tail-enders Mohammad Amir was batting on six and Yasir Shah on one as West Indies will look to bowl out Pakistan early on day two.
Pakistan, who won a good toss on a batting-friendly pitch, saw opener Sami Aslam (72), Misbah-ul-Haq (53), Younis Khan (51) and Sarfraz Ahmed (51) all failing to build on good starts.
That slump could hurt Pakistan's chances of whitewashing West Indies 3-0 after winning the first Test by 56 runs in Dubai and the second by 133 runs in Abu Dhabi.
More From This Section
Misbah had started his record 49th Test as captain -- bettering Imran Khan's feat of 48 Tests as captain -- on a good note when he won the third straight toss and instantly decided to bat but his batsmen played reckless shots.
Misbah was lucky to survive a close leg-before decision after West Indian captain Jason Holder took a review against Australian umpire Paul Rieffel's not out decision but television umpire Richard Illingworth backed up the on-field official on the basis of sound, which could have been an edge off the bat.
That left West Indian players aggrieved as it could have further hit Pakistan hard.
Aslam, who added 106 for the third wicket with Younis, also fell to an irresponsible reverse sweep off Bishoo after looking set for his maiden hundred, having hit seven fours and a six in his 172-ball knock.
Earlier, it was Gabriel who jolted the Pakistan innings
at the start with the wickets of Ali and Shafiq in the very first over of the match.
Ali, who scored a career-best 302 not out in the first Test, edged a lifting delivery from Gabriel to slip after Sami had taken a single off the first ball.
Asad Shafiq also survived just one delivery before being trapped lbw as that time Holder successfully challenged Reiffel's not out decision.
West Indies also made two changes from the Abu Dhabi Test, with fit-again wicketkeeper Shane Dowrich replacing Shai Hope and paceman Alzarri Joseph coming in for Miguel Cummins.