The world's two greatest tennis players go toe-to-toe once again as the ATP season reaches its climax with the final of the World Tour Finals at the O2 Arena tonight.
Picking a winner from Monday night's showpiece looks as tough as they come in sport, with Rafael Nadal looking to cap the most remarkable of years while Novak Djokovic is the reigning champion on a 21-match winning streak.
The season-ending number one spot belongs to Nadal regardless of the result but his opponent will be desperate to fire a signal of intent on reclaiming his status at the helm of the game.
The bookmakers make the world number two the slightly favourite with Sky Bet reporting a majority of support for the shorter-priced player, while offering 6/4 for Nadal to prevail at the season-ending event for the first time.
While the outcome is very much up for debate, two things can be concluded already - these two stand well clear of the rest of the field and will engage in a battle of attrition on Monday night.
Their dominance has been perfectly apparent throughout the week, wearing down their more aggressive opponents with relentless returns. Both cruised through the semi-finals with straight-set wins.
While both players are renowned for their resilience, history tells us that the first set will be crucial, with the loser of it only prevailing on three occasions from their 38 previous meetings.
Indeed, while epic battles typify duels between the duo, including that incredible Australian Open final last year, 19 of their 25 clashes in a three-set format have been decided in straight sets.
The 'King of Clay' leads the rivalry 22-16 but mainly due to his superior results on the red dirt, while they have one win apiece from meetings at the World Tour Finals since it moved to London.
As always, a gruelling battle can be expected tonight between these two competitors who have revolutionised the game with their physical capacities.
The powerful Nadal is doing unprecedented things to a tennis ball, with the relentlessly devastating revolutions created by his forehand making it kick up and bend in ways previously incomprehensible.
His equally intense opponent has turned his body into an elastic band on a tennis court, stretching and sliding to suck up the power of shots coming his way before flinging them back with remarkable accuracy.
Expect to see both step up their aggressiveness from showings during the week, with Djokovic closer to the baseline as he endeavours to reduce Nadal's preparation time, which is key to his forehand gaining governance of the court.
For me, the Serb's confidence to take the game to Nadal is the key and I'm backing him to be victorious in straight sets amid preferable conditions.
The Spaniard holds a solitary title in the environment in question and, while the conditions are among slowest you'll see in the indoors, Djokovic still holds the advantage.
Another interesting angle sits with the service preference, with Djokovic opting to serve first when presented with the choice while Nadal predominantly decides to recieve.
Therefore, backing the Serb to win the first set 6-3 looks to way to go given a solitary break is the most common way of a set being decided.
Djokovic to win in two sets - 11/8
Djokovic to win 1st set 6-3 - 7/2
Match to be decided in two sets - 4/6