8 players to have successfully defended their ATP Finals title

#7 Björn Borg (Successfully defended his title once)

Björn Borg

Björn Borg, the first player to capture 11 Grand Slam singles titles, is a two-time winner at the season-ending ATP Finals, then called the Masters Grand Prix.

In his 4th appearance at the ATP Finals in 1979 New York, two-time finalist Borg beat Vitas Gerulaitis in the final, for his first title at the tournament.

Borg returned the next year and beat Ivan Lendl in the 1980 final to record his first successful title defence at the ATP Finals.

#8 Ilie Năstase (Successfully defended his title 2 times)

Ilie Năstase

Ilie Năstase became the first debutant to win the ATP Finals, then called the Masters Grand Prix, when he dethroned the tournament's first champion Stan Smith in the 1971 final in Paris.

In a repeat of the previous year's title match, Năstase beat Smith in the 1972 Barcelona final to become the first multiple-time winner at the season-finale tournament and also the first player to win his first 10 matches at the tournament.

The Romanian made it a three-peat in the Boston final in 1973 when he beat Tom Okker in the title match.

Argentinian Guillermo Vilas ended the title-winning streak of Năstase in the 1974 final in Melbourne, the only time the tournament was played outdoors and on grass.

Năstase returned for his final appearance at the ATP Finals in 1975 where he beat local boy Björn Borg in the Stockholm title match to become the tournament's first four-time winner and the first player to reach four consecutive finals, streaks which would last for more than a decade.