Lee Westwood knows he can ill afford to rest on his laurels as he battles against injury and a challenge from his rivals to hold onto the World Number One spot at this week's World Golf Championships - HSBC Champions in Shanghai.
The 37 year old became the first European to top the rankings since Nick Faldo in 1994 at the weekend without even hitting a ball after Martin Kaymer could only manage 21st place at the Andalucia Valderrama Masters.
With the rankings calculated using a points average over a two-year period, Kaymer's failure to claim a top-two finish meant Westwood moved ahead of Tiger Woods and ended the American's 281-week reign.
It could, however, be a short stay at the top with Woods, Kaymer and defending champion Phil Mickelson all able to dethrone Westwood in Shanghai.
The Englishman's cause is certainly not helped by a lingering calf injury and he knows it will require all of his strength and ability to ensure he is still holding onto the Number One position come Sunday evening.
"It's one thing getting there, another thing staying there. It's obviously very close at the moment," said Westwood.
"It's going to be tough this week. I have to play well, which may not be easy because I'm bound to be a bit rusty because I've not played a lot just recently."
Westwood played a key role in Europe's Ryder Cup victory over America in October but has played in only one tournament since - the Alfred Dunhill Links Championship where his injury clearly gave him trouble.
"It (the injury) is still not right," he added. "But I was getting bored of sitting at home doing nothing and all of the people I've seen have said I can't do any more damage to it, so to come out and the walking around may do it a little bit of good."
Given his injury and what is at stake this week, Westwood could be forgiven for showing signs of feeling the pressure.
But having worked so hard to reach the pinnacle of the game he has no intention of relinquishing the top spot without a fight.
He said: "I don't feel any added pressure being World Number One. There's pressure but it's what you make out of it.
"It's unfortunate that my injury happened but you know, it's just a case of managing it at the moment and edging my way through."
Westwood tees off in the opening round at Sheshan International with former US PGA Championship winner Y E Yang and Mickelson.
The 40 year old had plenty of chances throughout the summer to claim the Number One spot but the best finish he could manage was a tie for eighth at the BMW Championship.
Mickelson revealed earlier this year that he was diagnosed with psoriatic arthritis but the four-time Major winner is confident his health issues will not affect his chances of success in Shanghai.
"I've been fortunate to win this tournament and I look forward to playing it every year," said Mickelson, who is making his fourth successive appearance at the event.
"I feel like I can put together a good week here and compete for the title."
