The twenty-time Grand Slam champion recorded a comfortable two-set victory over second seed Dimitrov.
Federer swept aside world number five Dimitrov 6-2-6-2 for his 97th title.
The legendary tennis player had entered the tournament as a wildcard and took advantage of Rafael Nadal's absence, who was the world number 1 until Federer won his quarter-final on Friday.
Federer, first became world number one in February 2004, and had not topped the rankings since October 2012. He, infact, slipped to a low of 17th in January 2017. (ANI)