It will be hard for Andy Murray to overcome the world's top three players at Wimbledon this summer, Barry Cowan told Sky Sports News.
Murray is still in search of his maiden Grand Slam while the players immediately above him in the rankings - Roger Federer, Rafael Nadal and Novak Djokovic - all have numerous titles to their name.
The Scot has been seeded fourth for the SW19 event, but Cowan feels there is a significant gap to the three front runners.
"Andy Murray is the fourth ranked player, the fourth seed and the fourth favourite," he said. "Those top three have shown, in how dominant they've been in the Grand Slams, that they're just a little bit ahead of the rest.
"For Murray to win Wimbledon he has to play incredible tennis because of how good the top end is. You've got to play great in the quarter-finals, semi-finals and final.
"My mind goes back to Murray's match against Rafael Nadal last year. Murray played unbelievably well for a set and at the beginning of the second set, then he missed a forehand and it all changed. You can't afford to have a blip like that if you want to win Wimbledon.
"Going into Wimbledon the favourites are the top three because there are very few areas in their games where they give you a chance to let you in."
Cowan also believes Murray will be hoping he isn't in the same half of the draw as Nadal - a man who's knocked him out three times in the past four championships.
"Murray will hope when the draw comes out that he's not in the same half of the draw as Rafa," said Cowan. "We know what has happened when Murray has played Rafa at Wimbledon."