Earlier, Djokovic won the group and qualified for the semifinals with a perfect 3-0 record.
The Serbian dominated the Belgian Goffin 6-1, 6-2 in 70 minutes to clinch his fifth consecutive semifinal appearance in London.
The four-time defending champion now awaits the second-place finisher in Group John McEnroe, which could be Andy Murray, Stan Wawrinka or Kei Nishikori.
Wawrinka takes on Murray on Friday afternoon and Nishikori meets Marin Cilic during Friday's evening session.