Novak Djokovic announces he has hired longtime rival Andy Murray to be next coach

"We played each other since we were boys - 25 years of being rivals, of pushing each other beyond our limits. We had some of the most epic battles in our sport. They called us game-changers, risk-takers, history-makers," Djokovic said on a video he posted to social media.

"I thought our story may be over. Turns out, it has one final chapter. It's time for one of my toughest opponents to step into my corner. Welcome on board, Coach - Andy Murray."

In March, after winning 12 Grand Slam titles in six years with coach Goran Ivaniseiv, Djokovic split from his longtime coach and has not hired anyone permanently since. 

Murray, 37, retired from competitive play after the Olympics in July and is looking forward to beginning his next chapter in tennis. 

"I'm going to be joining Novak's team in the offseason, helping him to prepare for the Australian Open," Murray said in a statement released by his management team. "I'm really excited for it and looking forward to spending time on the same side of the net as Novak for a change, helping him to achieve his goals."

Djokovic, also 37, and Murray were born a week apart in May 1987 and faced off 36 times in their professional career. Djokovic holds a 25-11 record over Murray, including Djokovic holding an 11-8 in finals, and 8-2 in Grand Slam tournaments. 

Djokovic beat Murray in the Australian Open four times; in 2011, 2013, 2015, and 2016. 

Next year's Australian Open starts on Jan. 12. 

The Associated Press contributed to this report.