Leg spinner Devendra Bishoo claimed four wickets on his debut to help West Indies skittle Pakistan for 160 on the second day of the first Test on Friday.
Some of Bishoo's excellent work was undone though when the home team slumped to 34 for two in their second innings at the close, a lead of 100 runs.
Devon Smith, whose place is likely to be questioned again, fell to Mohammad Hafeez's spin when the opener was trapped lbw for one playing a feeble stroke.
Pakistan then struck again when left-hander Darren Bravo was trapped leg before for eight by Saeed Ajmal.
Earlier, the Guyanese crowd were cheered by the exploits of the local spinner.
Bishoo picked up his maiden Test wicket when he trapped Misbah-ul-Haq lbw for two with a flipper, a delivery that highlighted his diverse repertoire.
Asad Shafiq also went leg before to Bishoo for two, after a West Indies review, and Mohammed Salman was dismissed for four in similar fashion following a straight ball from the spinner.
Captain Darren Sammy chipped in with two wickets as West Indies, who were bowled out for 226 in their first innings at the start of the day, put the tourists under pressure.
The 25-year-old Bishoo, composed, confident and showing no sign of nerves, struck again when he had Umar Akmal caught behind for 33 as he finished with four for 68 from 25 overs.
Pakistan's total would have been even worse but for an unbeaten 40 by Abdur Rehman.
Seamer Ravi Rampaul also returned figures of three for 27 to cap a good all-round performance in the field from West Indies.
Now they need a big innings from their batting hope -- Lendl Simmons (18 not out) -- and some of the stability in the middle order that has been missing in recent performances.
But Pakistan also have plenty of spin options and will fancy their chances of dismissing the hosts cheaply to set themselves an achievable target.