Jack Sock was quizzed thoroughly at the ATP Finals in London on all things British. The 25-year-old is the only American in the singles draw after having won his first ATP Masters 1000 in Paris just ahead of arriving in London. 

Sock was a great sport, even shouting out Judy Murray after a tricky question over which Murray brother he'd prefer to hang out with. 

While Sock dropped his debut match against Roger Federer, he managed to score his first win in three dramatic sets over Marin Cilic, 5-7, 6-2, 7-6 (4). 

Sock has Alexander Zverev left to play in round-robin play.