For those who spent yesterday spitting nails about what court they should or should not have been playing on, a healthy dose of Mario Ancic's perspective would have come in handy. By and large, tennis players are a favoured bunch, playing a sport for the most part in the fresh air, to stunning backdrops, for a decent remuneration. The courts are all green, all mown the same and all the same measurements. Get on with it.

Every once in a while something comes along that interrupts the beauty of everyday life and what had been taken for granted is to be cherished, sought after, dreamt about. I recall shaking Ancic's hand at Wimbledon last September - he walked over and proffered his, which shows what a well-bred man he is - during the Davis Cup World Group qualifier between Great Britain and Croatia and saying how glad I was to see him. Never more so.

He was just practising, his green shirt dripping sweat and, although not fit enough to play in the tie, he had wanted to feel the grass beneath his feet again. Six months earlier it was all he could do to climb out of bed and after 15 minutes walking like an elderly gentleman on Eastbourne promenade, he had to lie down again. Often he spent 18 hours a day in a darkened room, sipping soup and eating minute salad portions. Ancic was the victim of a bout of glandular fever so vicious that he wondered if he would play sport professionally again.

To see him reach the quarter-finals of Wimbledon yesterday was a fillip, and that is not meant as any disrespect to Fernando Verdasco, his Spanish opponent, who won the first two sets, led the fourth 4-2, 30-0 and broke Ancic to love when he first served for the match in the fifth. Verdasco was gradually beaten down by a 24-year-old who has simply willed himself back into grand-slam tournament contention. “I wanted to be back in this holy place,” he said.

And, holy of holies, he is in the thick of the tournament to such an extent he will play Roger Federer tomorrow - and it does not get much thicker than that. Especially because Ancic was the last man to beat Federer on grass, which, for the Swiss maestro, was 63 matches ago.

Freddie Rosengren, Ancic's Swedish coach, was in tears at the close of 3hr 48min of extraordinary tennis on No11 Court - he, more than anyone, knew what this personable Croat had gone through since February last year. Briefly, having played a Davis Cup match in Germany, Ancic woke unable to swallow or eat and was coughing up blood. “I had never felt as bad as I did there,” he said. The doctors diagnosed a severe case of flu, so Ancic flew to the next tournament in Marseilles, where, after the first four games of his first-round match, he could not move.

“I had a huge fever, I don't know how I got home to Croatia and they diagnosed me pretty quickly,” Ancic said. “I remember that it was a beautiful weekend, I wanted to walk on the beach, but after 15 minutes my legs gave out. My liver was completely gone, the enzyme count was rocketing - in the sky. I lost so much weight and my muscles were reduced because if you don't train for ten days, you start to lose muscle mass. I lost everything.”

Recuperation was slow and painful - one step forward, two back. He had shoulder problems, thyroid concerns, a stomach virus. You name it, Ancic suffered it. Which is why, as he has climbed back up the rankings, from No135 four months ago to No43, he has been cheered every step of the way. During his convalescence he took time out to complete a doctorate in law at Split University. His thesis was entitled “ATP Tennis, Yesterday, Today and Tomorrow”.

Yesterday Ancic was brilliant; today he will rest his heavy legs (he has a calf problem, but it is minor) and tomorrow, well, who knows what tomorrow will bring. Ancic helped Federer with information and support when the Wimbledon champion suffered a milder form of glandular fever this year. He did the same with Justine Henin when she was suffering. He is perhaps the nicest man to have pulled on tennis shoes.

True to his character - and if he has a chance in a thousand - Ancic will have to come at the world No1, he will bomb down his first serves, he will try to get to the net, he will attempt to disrupt Federer's rhythm. What is more important to him is that, after all his trials, he will walk back on to Centre Court again, taller and stronger than he had the right to be.