Novak Djokovic is looking forward to the "big challenge" of facing Andy Murray at the ATP World Tour Finals after both recorded opening victories in London.
Top seed Djokovic finds himself sitting on top of Group A after his 7-6 (7-4) 6-3 triumph over Frenchman Jo-Wilfried Tsonga on Monday night.
Next up for the Serbian in round-robin play on Wednesday is a clash with home favourite Murray, who came back from a set down to defeat Tomas Berdych in the opening singles match at the season-ending tournament.
"It's always a big challenge when you play Andy," Djokovic told Sky Sports.
"We've had some great encounters in the last couple of months, obviously remembering the final of the US Open that lasted almost five hours, then the last one in Shanghai.
"He's playing here at home in front of a big support, so I hope we can come up with some very big tennis for those that come and watch."
Djokovic - who will become just the 10th man to finish top of the world rankings in back-to-back years - was hardly short of support himself against Tsonga at the O2 Arena.
"It's really a pleasure to play here again. I was really looking forward to coming to London," he said.
"Over the years we've been coming back to play the World Tour Finals in this incredible stadium. We obviously enjoy this atmosphere and it's the last tournament of the year, so we are trying to give our best."