Boris Becker has said that Andy Murray and Novak Djokovic are currently rivaling each other in a similar way to how Roger Federer and Rafael Nadal have done so in recent years.
Murray, who beat Djokovic over five sets in the US Open final in September, will face the Serb in the group stages of the ATP World Tour Finals later this week.
"They are having a rivalry similar to the one we've seen between Federer and Nadal and a few of the finals we've seen have been amazing," said Becker.
"The way they have been playing would suggest they have pulled away but Federer has been the number one for a lot of the year and Nadal won the French Open.
"Tennis is a sport where people pretty much only remember your last one or two matches."
Murray faces Tomas Berdych later today, while Djokovic tackles Jo-Wilfried Tsonga.