Bulgaria's best tennis player Grigor Dimitrov achieved a dramatic victory in his first game in the ATP finals in London. In his debut in the eighth best tournament of the season, the 6th-placed Bulgarian defeated the world number 4 Dominic Thiem  with 6:3, 5:7, 7:5. The opening game of the Pete Sampras group was played in front of the full stands of the 20 000 seats O2 Arena, and it lasted almost 2 and a half hours.

"I was very nervous, I was training on this court, but today, when I first came out on the pitch in this atmosphere, before these fans, it was quite different," said the happy Grigor Dimitrov after his victory, "I am very pleased to have won." I play for the first time in this tournament, to play here is a dream, but I have not come just to participate, but to win, thank you for the support I received, it is great to play in front of my family and friends.