Novak Djokovic had longstanding rivalries with Federer and Nadal but more recently others players have stepped into those roles.
As time moves on, so does tennis change, for the most part. Novak Djokovic is still the top tennis player in the world yet a couple of younger players are slowly coming up and threatening his reign. Some of those have replaced Nadal and Federer as his longstanding rivals and in an interview with L'Equipe, Djokovic spoke about his 'new rivals'.
On Medvedev and Zverev he said:
“I can easily identify with that. The same [is true] for [Alexander] Zverev. He has the same approach. We can talk about a rebel’s mentality but not only that. We want to be authentic, stick to our values. When you make a mistake, I like it when you say: ‘I made a mistake’."
Djokovic further continued:
“If you want to criticise me, ok, it is your choice. I am not perfect but I am going to try to learn from all this. I don’t like it when people present themselves as perfect, on and off the court. That does not exist.”
He finished up with:
“That is why I appreciate [Zverev and Medvedev]. And they are incredible tennis players. I
would have hoped to have kicked their backsides a few times this year
in Tokyo or in New York but we always ended up joking about it. I love it. It is the rivalry of the Next Gen: Zverev, Djokovic, Medvedev!”