Jon Rahm is the second Spaniard to become world number one after winning the Memorial Tournament on Sunday.
The 25-year-old replaced Rory McIlroy atop the world rankings thanks to his victory at Muirfield Village.
Rahm joined the great Seve Ballesteros, who was last world number one more than 30 years ago, as the only Spaniards to reach the top ranking.
The win was Rahm's fourth on the PGA Tour and first of 2020.
Rahm spoke on Saturday about the significance of potentially becoming world number one, while describing the late Ballesteros as a "huge influence".
"It's obviously a big deal. I can't sit here and try to diminish it and avoid it because it would just be lying to myself because it is a big deal," he said.
"But it is a consequence of me winning. What's important to me [on Sunday] is hit good shots, be committed and get the job done.
"Everything else will be taken care of afterwards."