As a teenager, Andy Murray said that just making the world's top 10 was what he aimed to achieve from his career.
He has long since exceeded those aims. He is now potentially 13 days away from becoming the world number one for the first time.
After winning his second Wimbledon title earlier this year, the 29-year-old admitted that he would "love to get to number one".
"It's definitely a goal. It's something I spoke to my team about.
"I think before I was motivated genuinely solely really by the Slams. Whereas now I feel a lot more motivated throughout the whole year and at all of the events."
So, what does he have to do to complete his assault on the top of the men's game?
The quickest route to glory
With 2,415 points - more than are on offer for winning a Grand Slam - still separating him from top dog Novak Djokovic on the current rankings, it seems improbable that Murray will be top of the pops come 7 November.
But it is possible. This is how:
- 30 October: Murray wins the Erste Bank Open in Austria while Novak Djokovic opts to sit out the week's action. Gap down to 1,915 points.
- 5 November: Djokovic goes out at the semi-final stage at the Paris Masters. Gap down to 1,275 points.
- 6 November: Murray wins the Paris Masters title. Gap down to 875 points.
- 6 November: The points from the 2015 World Tour Finals - won by Djokovic - are wiped from the rankings record. Murray overtakes Djokovic to become world number one by 225 points.
The realistic route to the top
That is the shortest route from two to one. But not the most realistic.
"I'd have to win pretty much every match between now and the end of the year. And Novak would have to win hardly any," said Murray on his way to the Shanghai Masters title last week.
"I want to try and get there, but I don't think doing that by the end of this year is that realistic."
Djokovic does revel in the late-season indoor action in Europe.
He has won the Paris Masters in each of his last three attempts and the World Tour Finals for the last four years.
Instead Murray believes a strong finish to this season would give him a chance of toppling Djokovic in the first half of next season.
He has zeroed in on April 2017 as the point where Djokovic is most vulnerable.
Leading up to the start of that month are the Masters events at Indian Wells and Miami.
This year, Djokovic won them both, earning a maximum of 1,000 points from each.
That chunk of the calendar is where the biggest and easiest gains can be made by Murray.
The Djoker in the pack
Djokovic's hopes of staying at the top of the tree may depend more on psychology than mathematics and probability.
The Serb's strengths are many, but behind his razor-sharp returning, elastic limbs and eye-popping shot-making is a primal, insatiable will to win.
That edge to his play seems to have blunted for the past few months as he has struggled to fight his way out of the sticky situations that would usually prompt his finest performances.
He said that private, off-court issues hampered him in his third-round defeat to Sam Querrey at Wimbledon and, after he departed early and emotionally from the Rio 2016 singles draw, it seems the way he sees tennis has changed.
"A must-win type of mindset is not working for me anymore," he admitted in Shanghai.
"I'm still playing because I enjoy it, but that's my main priority.
"I try to look at things from different perspectives, from more human perspectives rather than from the perspective of a professional tennis player.
"I'm not in a need, you know, to achieve anything. You know, I feel like I have overcome that step."
Andy Murray would become the first British singles world number one, certainly as we understand it.
Fred Perry - who Murray followed as the next British winner of the Wimbledon men's title after a gap of 77 years - was ranked as the best player in the world on several occasions during the 1930s.
But, without an elite-level tour circuit and the game divided between amateur and professional, those lists were put together based on journalists' opinions rather than objective points tallies.
Since computerised rankings came in in 1973, it has been an essential part of all modern greats tennis CVs.
Bjorn Borg, John McEnroe, Murray's coach Ivan Lendl, Boris Becker, Pete Sampras, Andre Agassi and Roger Federer have all claimed top spot, along with less-celebrated names such as Chilean Marcelo Rios and Austria's Thomas Muster.
Murray would not be the first world number one in his family though.