The greatest know that brilliant achievements lie behind, but the view they crave is the one that offers the vista of further, unlimited triumph. It demands all their focus.
They have all, of course, been made by their past but they have been scarred by it, too. Andy Murray can look back on 2012 with immense satisfaction. An Olympic gold medal, a silver medal and a grand slam were all achieved with £3m in prize money tucked away in the swag bag. There was, though, the pain of losing a Wimbledon final and the recent irritation of finding match points no guarantee of match victories.
Sitting in a quiet room off the main arena of the 02 in London, the 25-year-old bows to the need to reflect on the past but only to preview the immediate future. The world No.3 is on the Greenwich Peninusla to take part in the Barclays ATP World Tour finals, an event that pitches the eight top-ranked players in the world against each other, with the winner pocketing £1.5m.
The stakes for Murray are higher than the substantial financial rewards. London offers Murray the opportunity to renew a rivalry with Novak Djokovic and to place a marker for what many believe will a 2013 season of revelation.
The theory is simple: Rafael Nadal is injured, Roger Federer is 31 and therefore the glittering prizes should be squabbled over by Djokovic and Murray. The obstacles to this eventuality are, of course, considerable. Nadal has come back from injury before and Federer has shown that London has the ability to revitalise him.
However, Murray seems more at ease with the rivalry with the Serb. Once it seemed that Djokovic – one week younger – was going to be the rival who served to remind Murray of what could have been.
The victories over the five-time grand slam winner at Flushing Meadows and in the Olympic semi-finals have given the Scot belief to accompany his ability. Is he now more confident when facing his friend?
'Yeah, I think that all the matches I have played with him this year have been incredibly close," he said. "The match at the Olympics, for example. There were a lot of long games and, in the second set especially, he had chances. At the US Open, the Australian Open, they were so close. I wouldn't say either one of us has had especially the upper hand this year, they have been incredibly physical matches, very, very tough. I hope it is the same again this week."
Murray is in the same group as Djokovic at the 02 with Tomas Berdych and Jo-Wilfried Tsonga hoping to bar the way to the knockout stages where the first two in group A face the best two in a group B comprising Federer, David Ferrer, winner in Paris yesterday, Juan Martin Del Potro and Janko Tipsarevic.
However, it is the growing rivalry with Djokovic that is slowly exerting a hold over the sport. Murray plays down any suggestion of an upheaval in the world order but quietly insists that the top three in the world have been extraordinarily consistent in the majors.
For the first time in six years, not one of the top four reached the quarter-finals of a Masters tournament, in Paris this week. But Murray has faith in the resilience of the elite. Of Federer losing to Del Potro in Basel, he said: "To me, that is not a major surprise. When it happens in the slams, when that starts happening more regularly in the slams, that is when you would see that guys were making a big breakthrough."
Djokovic, though, was more circumspect yesterday when talking about a mano a mano against a player he has known for more than 14 years.
He was predictably gracious about the Scot. "Andy has won his US Open title and he won it in great style and it wasn't easy for him after many years of being at the top but not being able to win majors," he said.
"Many people were questioning if he can really make it, but he has proven to everyone that he is a grand slam winner, that he is a champion. There is no question about it. He deserves to be mentioned in that group of top players in this year or in any of the past five years. He was always up there," said Djokovic.
But the Serb was keen to include Federer and Nadal in any conversation about rivalries.
"The four of us are really good players and we are trying to bring the sport to another level. It is nice to see that these rivalries are evolving, getting stronger and more competitive."
This competition will begin again today when Murray faces Berdych who is determined "to gain a small revenge" for his defeat in the US Open semi-finals.
The Scot has a comforting history of winning that peculiar duel in a New York gale but he also has the immediate back story of losing contests to Djokovic, Milos Raonic and Jerzy Janoiowicz after holding match points.
It is the loss to the 21-year-old Pole that upsets Murray the most.
"I just rushed and wasn't thinking really. I thought the match was won," he said, almost in bemusement at his innocence. "I don't think I will take anything granted here, that's for sure," he said in the manner of a grand slam winner.
His focus will be strong despite not having the most famous cheerleader in the world in his box. Just what did he make of the presence of Sir Alex Ferguson at the US Open?
"I didn't get to spend too much time with him, but it was obviously great to have him there. He is a legend, not just in his field, but in all sports," said Murray.
The young Scot now seeks to enhance his legend after the US Open. The road to triumph this week lies through Djokovic. It may always be thus.