Grigor Dimitrov won all five of his matches in London to win the biggest title of his career. His battle against Jack Sock in the semifinals didn't come easily, evidenced by an outrageous rally in the third set.

Over a minute of incredible play with powerful shots and high accuracy, Sock eventually fell to a volley that he didn't have the energy for.

Dimitrov rallied back after losing the first set to the American, 6-4, to win the next two, 6-0, 6-3. He ultimately went on to defeat David Goffin in the final for his first ATP Finals title in his debut.