In tennis a tournament win only feels right if you are undefeated. And I think that’s why Djokovic fought so hard against Medvedev. This was his fourth undefeated title, only one behind Federer and Lendl now. That said, I’m quite sure he will get another one, so this thread isn't intended to "downvote" him. On the contrary, he showed that a real champion wants to stay undefeated at all costs and he should have earned everyone's respect with his attitude.
Here I have the number of undefeated title runs for all those players who (officially) won the ATP Finals since 1970.
5
Roger Federer (6)
Ivan Lendl* (5)
* 2 of Lendl’s titles were in knockout format, so obviously the winner was undefeated. Also in one more title his last RR match wasn’t played.
4
Novak Djokovic (6)
3
John McEnroe* (3)
* 2 of McEnroe’s titles were in knockout format (same as for Lendl)
2
Ilie Nastase (4)
1
Björn Borg (2)
Lleyton Hewitt (2)
Andy Murray (1)
Michael Stich (1)
Daniil Medvedev (1)
Grigor Dimitrov (1)
Guillermo Vilas (1)
0
Pete Sampras (5)
Boris Becker (3)
Alexander Zverev (2)
Alex Corretja (1)
Andre Agassi (1)
David Nalbandian (1)
Gustavo Kuerten (1)
Jimmy Connors (1)
Nikolay Davydenko (1)
Stan Smith (1)
Stefan Edberg (1)
Stefanos Tsitsipas (1)
Here I have the number of undefeated title runs for all those players who (officially) won the ATP Finals since 1970.
5
Roger Federer (6)
Ivan Lendl* (5)
* 2 of Lendl’s titles were in knockout format, so obviously the winner was undefeated. Also in one more title his last RR match wasn’t played.
4
Novak Djokovic (6)
3
John McEnroe* (3)
* 2 of McEnroe’s titles were in knockout format (same as for Lendl)
2
Ilie Nastase (4)
1
Björn Borg (2)
Lleyton Hewitt (2)
Andy Murray (1)
Michael Stich (1)
Daniil Medvedev (1)
Grigor Dimitrov (1)
Guillermo Vilas (1)
0
Pete Sampras (5)
Boris Becker (3)
Alexander Zverev (2)
Alex Corretja (1)
Andre Agassi (1)
David Nalbandian (1)
Gustavo Kuerten (1)
Jimmy Connors (1)
Nikolay Davydenko (1)
Stan Smith (1)
Stefan Edberg (1)
Stefanos Tsitsipas (1)