Luke Donald, pictured, deposed Lee Westwood at the top of the rankings when winning last year's title
The battle to be the world's top-ranked golfer will again be a subplot of this week's PGA Championship which starts on Thursday at Wentworth.
Luke Donald, who deposed Lee Westwood at the top of the rankings when winning last year's title, is the only player who can topple current number one Rory McIlroy but needs to repeat his victory of 12 months ago to do so.
However McIlroy performs, Donald has to finish eighth alone or better to have any chance of reclaiming his place at the head of the rankings.
A win for Westwood, who displaced Tiger Woods as number one in October 2010, would leave him just short of top spot.
But US Open champion McIlroy is confident he has the game to see off his rivals and hang onto his title as the world's best golfer.
"You have to think you can beat everybody else," McIlroy told reporters after competing in the eve-of-tournament Pro-Am at Wentworth.
"You have to believe you are the best and I certainly believe that. It is just a matter of going out there and showing everyone else what I believe."
World number three Westwood, who missed out in a play-off to Donald last year, has a new caddy after his regular bag man Billy Foster injured his knee playing football ahead of Quail Hollow.
New Zealand-born Michael Waite, who won the US Open with Michael Campbell in 2005, has stepped in but Westwood admitted that Foster's absence was less than ideal.
Westwood said: "It's obviously quite disruptive. He is an integral part of the team. My game and results have obviously improved the last few years as a result of Billy being on the bag, so it is very disruptive.
"But I have got an able replacement and we will see how the next few weeks goes."
Donald will start the defence of his title playing with England's Justin Rose and Spaniard Alvaro Quiros for the first two rounds whilst McIlroy is grouped with three-time major winner Ernie Els from South Africa and Scotland's Martin Laird.
Westwood is grouped with Ireland's Graeme McDowell and Thomas Bjorn from Denmark.
There are a record number of 14 major champions in the field including Els who with his course designer hat on has made more changes to the course.
Two years ago Els was criticised by his fellow players for altering the course, particularly the par-5 18th that caused drama in last year's play-off when Westwood hit his approach into the water around the green.
Further tinkering ahead of the tournament a year ago also did not meet with the approval of many of the golfers with Ian Poulter being one of the loudest to vent his disapproval.
Els has made some minor modifications to the course for the flagship event of the European Tour and is convinced he has finally come up with a fair test of golf.
"I think the guys will have a lot better scoring opportunities," Els told reporters at Wentworth.
"It is a par 72, six-under won last year. I think 14 or 16-under is going to be the winning score and hopefully we will have a lot more smiling faces from the players this year."
The 18th has provided some grandstand finishes over the years and Els believes the latest changes, with players hitting their approach shots from an elevated part of the fairway to a small green surrounded by water will provide the same this year.
He added: "It is going to be a great finishing hole. There is water so there is risk and reward if you want to go for it. It is an exciting finish and you can make an eagle there now."
Meanwhile England's Simon Dyson, the reigning Irish and Dutch Open champion, has withdrawn from the tournament with a hip injury.
Dyson, who pulled out of the Players Championship in Florida two weeks ago, is replaced in the field by Dutchman Maarten Lafeber.