Answer
Grigor Dimitrov's highest ranking was achieved on 20 November 2017, when he was ranked world No. 3. Dimitrov has been ranked in the top 10 since April 2014, and has reached the final of a Grand Slam tournament twice, losing in the final of the 2017 Australian Open to Roger Federer and in the final of the 2019 Wimbledon Championships to Novak Djokovic.