Bulgaria's most successful men's tennis player, he's the first Bulgarian to earn a top 10 ranking and the first to earn more than $1 million in his career. He first broke into the top 10 in 2014.
He won the European U14 Championship at age 14.
He was a Junior Wimbledon and US Open champion in 2008. He was the world number 1 as a junior player.
He was defeated by Marin Cilic in the first round of singles play at the 2016 Olympic Games.