Arthurton, a specialised middle-order batsman contributed immensely to his side by scoring a useful 33 off 44 balls with two fours and then inserted the pressure on the Pakistanis by striking at regular intervals whenever they showed signs of taking control of the match. He was picked the Man of the Match.
After opener Saleem Elahi hit a dashing 46 off 79 balls and ran himself out, only Ijaz Ahmed and Salim Malik looked the dangermen for the Windies.
Elahi and Azhar Mehmood added 43 runs for the second wicket and then Arthurton broke through taking Mehmood's wicket to signal a Pakistan struggle.
The West Indies electing to bat reached a defendable total of 289 for 9 in 50 overs. In reply Pakistan were 259 for 9 in their 50 overs.
Umpires Srinivas Venkatraghavan and Steve Bucknor (West Indies) will officiate the semi-final match between Sri Lanka and South Africa today. The third umpire will be David Shepherd of England and match referee Raman Subba Row also from England.
Friday's match: Sri Lanka v South Africa (semi-final)