Roger Federer, Kevin Anderson, Kei Nishikori and Dominic Thiem talk about their 3rd round robin match at the ATP Finals in London.

Selected by the organizers, here are the Top 10 Moments of the first week of this 2018 US Open.

John Isner: ''I never could have imagine it. It's the best moment of my career''

Stefanos Tsitsipas sprints to a drop volley and whip it past Novak Djokovic in Madrid

Stefanos Tsitsipas (after beating Kevin Anderson in Toronto Masters 1000 SF) : ''It's amazing. I couldn't achieve anything better in one tournament.''