Andy Murray says the jump from number two to number one in the world rankings is the hardest of all, as he stands on the brink of surpassing Novak Djokovic at the summit.
A win for Murray at this week's Paris Masters would be enough to secure the number-one ranking, as long as Djokovic does not reach the final.
But Murray is cautious not to get ahead of himself.
"I get a step closer with every win but it's still a long way from here," he said after securing his seventh title of the season, beating Jo Wilfried Tsonga at the Erste Bank Open in Vienna.
"From two to one seems a small jump in a way but it's the hardest one to make.
"To go from 100 to 50 is more spots but is a lot easier."
Discussing his 6-3 7-6 (8-6) win against Tsonga, Murray added: "I was thinking more about how you are going to win the match rather than what it would mean if you did win it.
"But obviously it's nice to win my seventh tournament. A lot of them have come in the last few months.
"After the Australian Open I struggled a little bit for a couple of months but the last few months have been very good."