Bulgaria's Grigor Dimitrov holds the trophy as he celebrates winning his men's singles final match against Belgium's David Goffin on day eight of the ATP World Tour Finals tennis tournament at the O2 Arena in London on November 19, 2017. Dimitrov won the match 7-5, 6-4, 6-3. / AFP PHOTO / Glyn KIRK (Photo credit should read GLYN KIRK/AFP/Getty Images)

Grigor Dimitrov has claimed the biggest title of his career, winning the season ending ATP Finals in three sets over David Goffin.

Dimitrov, who won 7-5 4-6 6-3, became the first debutant to win the event since 1998.

The win sees the Bulgarian finish the year ranked a career-best No.3 in the world behind Rafael Nadal (No.1) and Roger Federer (No.2).

Dimitrov dispatched Goffin 6-0, 6-2 when the pair met in the group stage, however, the Belgium proved a far tougher opponent this time around. Dimitrov was broken twice in the first set, before coming back to when the opener.

Both players found their rhythm on serve in the second set, with the first break point of the set coming in the sixth game, with Goffin took full advantage of.

Dimitrov managed to break the Goffin serve at 3-2 in the third and despite Goffin saving three match points, went on to claim the third 6-3.

The last player to win the tournament in their first year was Alex Corretja in 1998.