The Mexican Open was Nadal's fourth win in a row, and he maintained his perfect start to the year.
At the end of last year, Nadal thought he might have to retire because of a foot injury, but he has won all three tournaments he has played this year.
The Spaniard won his 21st major title at the Australian Open.
The Spaniard said that at the start of the year it was unimaginable.
Nobody would have believed it a month and a half ago.
Nadal has a 15th victory to his name, which is the best start to a season he has ever had.
The fourth seed, who beat the world number one in the semifinals, won the title in Acapulco without dropping a set.
It is the fourth title for Nadal in the Mexican city and he has won his first as an 18-year-old in 2005.
Nadal is the tournament's youngest and oldest champion.
A finely balanced opener swung the way of Nadal when he converted the only break point of the set in the fifth game and served out without serious pressure from Norrie.
Norrie, who is ranked 12th in the world, had won his previous eight matches and claimed the title in Delray Beach last week.
The British man was able to break back for the first time in the second set, but his opponent took control with four straight games.
The pick-up volley from Nadal set up two championship points and he took the first when Norrie hit a forehand long.
Rafi doesn't give you any free points and if you give him one or two he takes advantage of them.
It is impressive to see how he does it.