After fog wiped out the morning session's play, home captain Shan Masood's decision to bat at Multan Cricket Stadium on Friday appeared to backfire as Pakistan slumped to 4-46 when Seales dismissed Babar Azam caught behind.
Shakeel (56) and Rizwan (51) then propped up Pakistan with an unbroken 97-run stand for the fifth wicket before bad light stopped play.
West Indies' Jayden Seales took three wickets early to put pressure on the hosts. (AP PHOTO)
West Indies began with Gudakesh Motie's left-arm spin on a track which offered significant turn for a first-day wicket, but it was Seales who dented Pakistan's top order.
Opener Muhammad Hurraira made six before edging one to West Indies wicketkeeper Tevin Imlach, who was also making his Test debut.
Kamran Ghulam (five) fell lbw after not offering a shot to an inswinging delivery from Seales, who went on to dismiss Babar caught behind.
After a lengthy chat with Saud, Babar, who made eight, decided to review the decision. Replays confirmed he had nicked the ball.
"We need to continue bowling the good balls," Seales said.
"As spinners or as fast bowlers, there's always something in the pitch for us. It's a matter of just bowling our good balls for as long as possible.
"I think 250-odd is probably a good score on this pitch."Â
