The 33-year-old Bulgarian athlete acknowledged that it “takes a little piece” away from him to watch his rivals quit the sport.
Thiem lost to Luciano Darderi in the first round of the Vienna Open this week, which was his last encounter.
The 31-year-old Austrian, who won the 2020 US Open and rose to a career-high ranking of world No. 3, lost four of his seven matches to Dimitrov.
Next month, following the 2024 Davis Cup Final 8 stage in Malaga, Rafael Nadal will end his career. In his 15 encounters with the 38-year-old Spanish legend, who won 22 Grand Slam titles, Dimitrov only managed one victory.
It’s depressing. Dominic was also in Vienna when I saw him a few days ago. That is something I can’t help but consider as well,” Dimitrov told Eurosport.
“Everything has a beginning and an end, of course, but it takes a little piece away from you to see your childhood rivals and these guys who are pushing you to succeed. That’s just the way it is.
“Off the court, it was a lot of fun; we were always making fun of each other, and I don’t see that anymore, but I have respect for the younger generation and everyone who is playing out there.”
“I have nothing but respect for these players, but I miss that healthy competitiveness.”
The world No. 9 also disclosed that he has no immediate plans to discontinue his own career.
“I’m not that close to the end, but I’m closer than a lot of the players,” Dimitrov continued, acknowledging that everyone’s turn would come.
But I’m still playing, I’m still a contender, and I’m going to fight to the very end to maintain my position at the top.
“I’m more than content if my body permits me to do the things I’m doing at the moment.”