The O2

Grigor Dimitrov has his first marquee title after beating David Goffin to win the ATP Finals

Grigor Dimitrov has his first marquee title after beating David Goffin to win the ATP Finals

Grigor Dimitrov claimed the biggest title of his career at the season-ending ATP Finals on Sunday, prevailing on his fifth match point to beat David Goffin of Belgium 7-5, 4-6, 6-3.

The sixth-seeded Bulgarian won in 2 hours 30 minutes 15 seconds for the longest best-of-three sets final in the tournament's history. It was more than 11 minutes longer than Roger Federer took to beat Jo-Wilfried Tsonga in 2011.

Dimitrov won all five of his matches at the O2 Arena to become the first player to win the elite season-ending tournament on debut since 1998, when Alex Corretja of Spain triumphed in Hanover.

Goffin saved three match points on his own serve, but Dimitrov kept his...