Fast bowler Mohammad Abbas struck early to leave the West Indies reeling at 85-5 in their second innings after Pakistan were bowled out for 282 on the third day of the first Test, keeping the tourists firmly in contention.
Resuming their first innings in reply to the West Indies' 311, Pakistan were dismissed for 282, conceding a 29-run first-innings lead to the hosts.
Pakistan's innings was anchored by Shan Masood, who produced a superb 109, while Imam-ul-Haq contributed 63. Captain Babar Azam made 23, Salman Ali Agha scored 20, Mohammad Rizwan added 12, and Aamir Jamal was dismissed for 3.
For the West Indies, Justin Greaves starred with the ball, claiming five wickets, while Kemar Roach and Shamar Joseph picked up two wickets each.
Earlier, the hosts posted 311 in their first innings, thanks to Shai Hope's 92 and Keacy Carty Hodge's 84.
Shamar Joseph scored 23, while Tagenarine Chanderpaul and Jyd Goolie Jangoo contributed 21 runs each. Justin Greaves made 15, Brandon King scored 12, and Roston Chase added 10.
Pakistan's bowling effort in the first innings was led by Mohammad Ali, who took 4 wickets for 50 runs.
Mohammad Abbas claimed three wickets, Khurram Shahzad picked up two, while Aamir Jamal dismissed one batter.
In the West Indies' second innings, Mohammad Abbas once again made an immediate impact, reducing the hosts to 62 for 4 by stumps and putting Pakistan in a strong position as the first Test heads toward an exciting finish.