The victory brought Murray his sixth ATP title of a memorable 2016.
The Scot, 29, also added his second Olympic and Wimbledon titles on his way to the top of the rankings.
On Monday he will be officially confirmed as Britain's first singles number one since computerised rankings were introduced in 1973.
Murray's ascent was confirmed by Milos Raonic's withdrawal from Saturday's semi-final with a leg injury, but the hype around his accomplishment did nothing to knock his concentration.
He now heads to the season-ending World Tour Finals as top seed for the first time - but if previous number one Novak Djokovic wins every match at the Finals he will reclaim the top ranking he held for 122 weeks.
The draw for that competition takes place on Monday at 15:00 GMT.
He now heads to the season-ending World Tour Finals as top seed for the first time - but if previous number one Novak Djokovic wins every match at the Finals he will reclaim the top ranking he held for 122 weeks.
The draw for that competition takes place on Monday at 15:00 GMT.
