Khan followed his first innings four-wicket haul with 5-50 as the West Indies were bowled out for 123 in the second innings on Sunday after being set a target of 251 on a spinning pitch.
Alick Athanaze made a fighting 55 off 68 balls before he became Khan's fifth victim, with inexperienced West Indies resistance folding in the second session on day three.
Khan replicated his first-innings show with the new ball by yet again removing the top four batters as the tourists limped to 5-54 inside the first session, after which 11 of the 12 wickets had fallen to spinners.
Leg-spinner Abrar Ahmed, who shared the new ball with Khan, claimed figures of 4-27 that included the wickets of Kevin Sinclair (10) and Gudakesh Motie (0) off successive balls with both edging to Salman Ali Agha in the slips.
In a sensational two-and-a-half hour hour first session, left-arm spinner Jomel Warrican finished with a career-best 7-32 as Pakistan's batters also struggled on their own spin-friendly pitch.
Warrican featured in all but one dismissal in Pakistan's second innings as the home team was bowled out for 157 runs after resuming on 109-3.
That gave Pakistan an overall lead of 250 runs after West Indies conceded a 93-run first innings lead when dismissed for 137 inside one session on day two in reply to Pakistan's first inning 230.
Khan removed Kraigg Brathwaite (12), Mikyle Louis (13), Keacy Carty (6) and Kavem Hodge (0) for the second successive time in the match as the tourists' ploy to counterattack the off-spinner failed as slow bowlers gained great purchase off the sluggish surface.
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