Novak Djokovic says a challenging 2018 taught him a lot about himself and provided a platform to re-evaluate his priorities.
Djokovic underwent elbow surgery in January and slipped out of the world's top 20 as he battled to recover his form.
By the end of the season, the Serbian had returned to the rankings summit and had two grand slam titles under his belt, taking him to 14 over the course of his career.
"It has been an exciting 12 months," Djokovic said ahead of the World Tennis Championships.
"Twelve months ago, I was still carrying the injury of the elbow, which two months after that resulted in surgery."
"Post-surgery, I was 22 in the world, and in four or five months, I was number one, so it has been a rollercoaster ride to be honest and I am very grateful for that."
"I am grateful that this season has taught me a lot about myself as a tennis player and as a person. I really had to dig deep to sort of turn the table in my favour. I had to understand my game in every aspect in order to get back to where I am."
"Hopefully I can take the confidence that I had in the second half of the season into the first half of 2019."
Djokovic added that he was now taking a different approach to his career.
"I feel I am not prioritising success on the tennis court for the sake of success only as I used to do probably until about five years ago," he said.
"For me, tennis is more of a platform now for other things – for the values that I want to share and the messages that I want to give out to the young generation."