Pakistan's margin of victory was the second best in the shortest format behind Sri Lanka's 172-run win over Kenya in the 2007 World T20 at Johannesburg.
Pakistan thrashed a jet lagged West Indies by 143 runs in their Twenty20 opener on Sunday for the second biggest margin of victory in top-level T20 cricket. (MATCH SCORECARD)
West Indies collapsed in Karachi to its lowest ever T20 score of 60 in 13.4 overs after opting to bowl after only arriving in the country late Saturday night.
Pakistan scored its joint highest T20 score of 203-5.
In reply, only Marlon Samuels (18), Rayad Emrit (11) and Keemo Paul (10 not out) got into double figures as West Indies crumbled against Mohammad Amir (2-3), Shoaib Malik (2-13) and Mohammad Nawaz (2-19).
"Obviously there will be a bit of jet lag, but I think our performance just wasn't good enough," West Indies captain Jason Mohammed said.
Pakistan's margin of victory was the second best in the shortest format behind Sri Lanka's 172-run win over Kenya in the 2007 World T20 at Johannesburg.
World T20 champion West Indies' previous lowest total in a T20 international was 79-7 against Zimbabwe at Port of Spain in 2010.
"Losing three wickets in the first two overs put you in a lot of pressure ... your three top-order batsmen," Mohammed said. "It's just for us to get a better start, lay a better foundation and try to build some partnerships."
Earlier, debutant Hussain Talat top scored with 41 and Shoaib Malik provided the ideal finish with an unbeaten 37 off only 14 balls after West Indies won the toss.
Pakistan's total matched its previous best of 203-5, scored against Bangladesh in 2008 at the same National Stadium in Karachi, which was hosting an international match after nine years on Sunday.
West Indies' players looked visibly underprepared on the field after taking a long flight from home and preparing with a 90-minute workout at the stadium before the toss.
Left-arm spinner Veerasammy Permaul was stretchered off the field and taken to the hospital for precautionary X-rays as he twisted his left ankle in his follow through in his first over and the newcomer could not bat for West Indies.
Talat featured in a 75-run third wicket stand off 49 balls with captain Sarfraz Ahmed (38) before both batsmen fell in successive overs to make it 150-4 in the 17th over.
West Indies had its chances to contain Pakistan's late acceleration but debutant Keemo Paul (1-26) missed return catches of both Malik and Ashraf off successive deliveries. In the same 18th over, he had earlier clean bowled Pakistan newcomer Asif Ali for just one.
Malik cashed in on the opportunity to smash two sixes and two fours off Rayad Emrit, who conceded 23 runs in the 19th over and then Kesrick Williams went for 21 runs in the last over.
The southern port city last hosted an international game in 2009 when Sri Lanka played a test match before an attack by gunmen on its team bus in Lahore shut the door on international cricket in Pakistan.
Six Pakistan policemen and two civilians were killed in that attack, and six members of the Sri Lanka team were injured.
Gradually the Pakistan Cricket Board is trying to convince foreign teams that it's safe to play cricket in the country with Lahore hosting Zimbabwe, a World XI, Sri Lanka and a Pakistan Super League final over the last three years.
Karachi hosted the PSL final last week, with several foreign players competing in front of a capacity crowd.
However, at least four top West Indies players - Jason Holder, Carlos Brathwaite, Chris Gayle and Evin Lewis - pulled out of the three-match T20 series against Pakistan apparently due to security concerns.
Around 18,000 spectators watched Sunday's game.
"It has been very nice coming here ... we feel very safe," Mohammed said.
