TENNIS: The latest battle between Andy Murray and Novak Djokovic at the ATP Tour Finals could be their greatest.
What started as friendly rivalry 15 years ago when they first met in European junior tournaments has now reached a new level as their fight to end the year as the world No.1 comes to a head in London.
Murray last week ended Djokovic's 122-week reign at the top when the Wimbledon champion became the first British man to top the ATP rankings.
But the Scot possesses just a 405-point lead over the Serb and can be overtaken if he doesn't match or better his rival's performance at the season-ending event at the O2 Arena.
As the top two seeds, the pair has been drawn in different groups of the eight-player tournament, and won't meet until at least the semi-finals.
If their 35th ATP Tour meeting comes in the final, it will be the first time since 2001 when Lleyton Hewitt usurped Gustavo Kuerten that the No.1 ranking as changed hands at the Tour Finals.
Murray has enjoyed an incredible 11 months on and off the court in which he has won Wimbledon for the second time, claimed a second Olympic singles gold medal and, most importantly, become a father to baby daughter Sophia, which could be the secret to his success.
"It has distracted me in a good way,” Murray said. "All of my focus isn't on tennis now, which is a positive.
"I'm not dwelling on wins and losses as much. I feel a lot more level-headed ... I'm not as up and down. I just feel a lot more stable.”
Djokovic, who begins his Tour Finals campaign against Dominic Thiem, has won the season-ender the past four years. Another title would equal Roger Federer's record of six.
He holds a remarkable 23-0 record against Milos Raonic, Gael Monfils and Thiem, who comprise his group-stage opponents.
Murray, who has never been past the semi-finals of the event, takes on Stan Wawrinka, as well as Japan's Kei Nishikori and Croatian Marin Cilic, who have both beaten the Scot this year.
Murray takes on Cilic on Tuesday morning (6am AEST).
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