The tourists, set an improbable victory target of 444, went to lunch on the fifth and final day on 144-4 in their second innings, with Shivnarine Chanderpaul on 18 and Dwayne Bravo on six.
Pakistan dismissed Lara (49) and Runako Morton (16) to press home for their second win in the series after winning the first Test by nine wickets in Lahore. The second Test ended in a draw at Multan.
Skipper Lara and Ramnaresh Sarwan survived the first 90 minutes of the extended two-and-a-half hour session after the West Indies resumed at 39-2.
Lara and Sarwan played cautiously and negotiated Pakistan's pacemen Umar Gul and Shahid Nazir on a pitch which had eased out for batting.
Lara, who needed 96 to become the first man to score 12,000 Test runs, was dismissed off an uppish drive off Gul which was smartly snapped by Shoaib Malik at mid-off. Lara hit nine boundaries during his 92-ball knock.
Sarwan, who regained his place in the team after being dropped in the second Test, had to return to the pavilion after he was hit on the right foot by a full length delivery from Gul.
Sarwan, who has gone to hospital for an X-ray, had made 35.
Morton hit two boundaries and a six off Danish Kaneria before giving the Pakistani leg-spinner a return catch to leave the West Indies at 4-126.
No team in history has chased more than the 418 which the West Indies achieved for the loss of seven wickets against Australia in St John's, Antigua in 2003.
Pakistan 304 and 399 for 6 decl Vs West Indies 260 and 144 for 4 (Brian Lara 49, Sarwan 35 retd hurt, Chanderpaul 18 n o; Gul 2 for 66, Nazir 1 for 36, Kaneria 1 for 30)