Tim Henman launches his bid to reach the Wimbledon semi-final for the fifth time on Wednesday with the support of two of the game's legends.
But both John McEnroe and Boris Becker warned the British number one not to underestimate unseeded Mario Ancic of Croatia.
Henman and his 20-year-old opponent have never played each other before but 6ft 5ins Ancic, a tennis disciple of Goran Ivanisevic, is recognised as one of the most dangerous floaters in the draw on a surface which suits his big-serving game.
He has the scalp of reigning champion Roger Federer, who he beat in the first round two years ago, to prove it.
"Tim is playing much better when he's not supposed to win easily," said Becker. "He does not have the game to blow away opponents so he has to find a way to win the points but he has proved in the past that he has the ability to beat Federer and Roddick.
"Yes, he has the weapons. His problem is to get to the semi-final without losing too much energy. He always struggles when he is supposed to win easily."
McEnroe also added his warning, not that it will lower the expectations of a Centre Court crowd who are beginning to believe that this really could be the year when Henman ends the 68-year wait for a British men's singles champion following his thrilling fourth-round triumph against Mark Philippoussis.
"In his first three matches he did not play up to his capabilities," said McEnroe, speaking at an event launching the Stanford Financial Champions Tour Rankings.
"I think he did against Philippoussis. It would have been nicer to win it easier but then it would not be Tim Henman. It always seems to be a rollercoaster.
"Henman could be a programmer for the BBC. The ratings must be very good. But Ancic is very dangerous. He beat Federer here two years ago. I would pick Tim to win but he's got to be ready. Ancic is dangerous."
