He couldn't let up because there was always someone behind him, someone aiming to knock him off his perch as the No. 1 men's tennis player in the world.
At the 2016 Australian Open — the third in his astounding streak of four straight Grand Slam titles — Novak Djokovic used an interesting metaphor to explain why he considered complacency his toughest foe. The wolves who were climbing up the mountain to pursue him, he said, "are hungrier than the wolf standing on the hill," and he meant to do all he could to keep those rivals, those wolves, at bay.
For a while, he did. But he wasn't so hungry anymore after he won the French Open last June to fill in the only significant blank space on his stellar resume, and the wolves overtook him.
Djokovic lost his No. 1 ranking to Andy Murray and lost some of his confidence, resulting in a number of early defeats. His third-round loss to Sam Querrey at Wimbledon last summer was a shocker, and his loss to Stan Wawrinka in the U.S. Open final fueled whispers that something about him and his game seemed off. His second-round loss to Denis Istomin at this year's Australian Open triggered alarms.
Was he injured? Tired? Was his heart still in it?
Looking back Thursday, ranked No. 2 in the world as he prepared to begin defense of his title at the BNP Paribas Open this weekend, Djokovic acknowledged he had experienced an emotional letdown after his long-awaited French Open triumph. Finally, he said, his hunger is returning, and he expects the results to soon reflect that.
"Now I'm at a better place," he said, "so I hope and I believe that I'm heading in the right direction."
In winning Wimbledon and the U.S. Open in 2015 and the Australian and French Opens in 2016, Djokovic became the first men's player to win four straight Grand Slam titles since Rod Laver did it in 1969. Prevailing on the clay of France's Roland Garros stadium ended a quest that had dominated Djokovic's every thought, and his success solidified his place among the game's greats.
"Winning the French Open for the first time and crowning that couple of years of consistent, high results was magnificent. I really gave it all and French Open was always one of the top priorities the last couple of years," he said. "But on the same side, it took a lot of emotions and energy out of me and took some time to reflect on things. And then I had to start re-motivating myself and get back on track and I feel like right now it's much better than it was, especially in the second part of the last season. Particularly after the U.S. Open, I had those couple months where I wasn't myself on the court."
He knows now that he should have taken a break after the French Open to recharge emotionally and recast his goals. But second-guessing himself isn't part of his life philosophy.
"It didn't happen and I kept on going. And I'm not regretting it because I believe there was a lesson to be learned from that," he said. "I think having the four, five months of the second part of 2016 was actually very important for me, for my growth as a player and as a human being. I learned a lot. I keep going and obviously I'm motivated to keep playing on a very high level."
He faces a tough draw here, placed in the bottom quarter of the draw with Roger Federer, Rafael Nadal, and the dangerous Juan Martin Del Potro. Also in that quarter is Australia's Nick Kyrgios, whose serve was a prime weapon in his recent quarterfinal upset of Djokovic at Acapulco.
"This is probably one of the toughest draws that we all had," Djokovic said. "This is a very strong field. It's one of the strongest tournaments we have in sports. Everybody wants to do well. The draw is something you can't affect. I guess you have to accept it and deal with it."
He's dealing with it from a different perspective than he was even a few months ago. He said he feels revived, and that confidence and competitiveness have replaced the complacency he felt after the French Open. He's not the wolf standing on top of the hill but he wants to get back there.
"I guess I'm one of the wolves going up now and I'm hungry. But I'm not the only one," he said. "If I am not hungry to have success in this sport I wouldn't be sitting here talking with you and playing this tournament. I've achieved so much in my career that I'm very content with and I can easily stop today and say, 'OK, it's been enough.' But I keep going because I have that drive in me still and I have that flair. As long as that's present I'll keep on playing."