Colin Montgomerie believes only four players can win the Open.
Tiger Woods, Lee Westwood, Justin Rose and Paul Lawrie are the players equipped with the abilities needed to succeed at Royal Lytham & St Annes, Montgomerie told BBC Radio 5 live.
"There are three technical systems they've got to have and they need all three to win," said Montgomerie.
"There's only a few that fall into every category. One of those four is going to win."
The 2010 Ryder Cup captain said some players were hopeful of winning the 141st Open, which gets under way on Thursday, but only players who believed they could win it would be successful.
He said he doubted whether a number of highly ranked players truly believed they could win it, naming Hunter Mahan, Bubba Watson and Sergio Garcia among them.
And on world number one Luke Donald he said: "Does he truthfully believe he can win the Open? I would have to say yes - but only just."
The 49-year-old Scot, who has played more than 500 European Tour events in his professional career, said the first key skill for Open success was having a "go to" shot off the tee.
He explained: "They've got to have a safe shot off the tee. Round here especially, because it's very tough.
"Secondly, they have to hit the ball or have the ability to hit the ball low on cue because it's going to be breezy.
"The third is that they are going to have to be very good from three to eight feet.
"In my view Justin Rose falls into that category, Tiger Woods does, Lee Westwood does and Paul Lawrie does."