“I see it's still raining,” Pete Sampras says, chuckling. The serial plunderer of grand-slam titles is back in London, six years and five months on from the moment when, recalling its horror with a vivid clarity, “Wimbledon, my last refuge, turned into the focal point of my demise.” In his book, A Champion's Mind, Sampras writes heart-wrenchingly about the second-round defeat in 2002 by George Bastl, of Switzerland, on the No2 Court that, unaware to him, is to become as much of a relic as his playing style.

The 37-year-old usually spent a summer month here, picking up Wimbledon singles titles as one does apples from an orchard. To find him here in December is a real boon and to think that the British public has not seen the last of that familiar Sampras crouch, unwind, blurring service motion, pitter-pat to the net and effortless volley warms the cockles on a rotten afternoon.

The seven-times Wimbledon champion is here to play in the BlackRock Masters, a convivial gathering of chums, and the odd non-chum, who still find favour taking a swipe at a fuzzy yellow orb. Their bones creak a bit more, but competitive juices still flow. Sampras, though, was the last player expected to dust down his trusty Wilson and embrace nostalgia.

“Yup, I was top of the list to give this a miss, but I didn't understand fully how tricky retirement would be,” he said. “Every athlete will tell you, when they stop at a young age [he was 31] it is tough to find the kind of fulfilment you want. Some need to come out of retirement to find it, people get bored, they want to play at the level they once enjoyed - but that wasn't me. I was never in it for the money, or the limelight. I played to win.

“Then, after three years, I simply wanted to feel young again. I had put on a bit of weight, I didn't do much of anything apart from the golf and the poker, then I'd wake up and say, 'What do I do today?' I felt like I needed something to get me fit again. The lifestyle I have now, with a bit of tennis thrown in at a schedule that suits me, has made me a better husband and father. When you're not doing much of anything in your day, you lose your patience. There is no book on how to retire properly.”

After the Bastl bombshell, there was time for Sampras to gather his thoughts and rouse himself to a last hurrah, the 2002 US Open, his fourteenth and final grand-slam title, but that was it, the tank was on E. He departed with few regrets, except one, the Wimbledon afternoon on which he could not summon what used to come to him like running water and defeat a player he had never seen before and hopes he will not see again.

Sampras recalls losing the first two sets. “I kind of lost my way,” he said. “My confidence had been eroding and now big chunks of it were crumbling and falling off, by the minute.”

He fumbled around in his racket bag and found a letter written by Bridgette, his wife who was pregnant with his first son, Christian. It began: “To my husband, the seven-time Wimbledon champ”, which was telling him to remember who he was and what the tournament meant to him. Sampras, admitting that the letter freaked him out, won the next two sets but “was never out from under the cloud. I felt utterly empty. I had spent more than a decade beating people for a living, that was what I did, who I was. I had to ask myself if I was still that person.”

Though he wants to succeed this week, a defeat or two is easier for him now; he will even smile at a John McEnroe tantrum - the pair meet in an emotion-invoking first round-robin match this evening. “The public want to see me at whatever my best is these days,” Sampras said.

Far from the senior circuit, Sampras knows that Roger Federer is within one of his record of 14 grand-slam titles and accepts its loss to the Swiss as an inevitability. If the record hangs on Wimbledon next year, Sampras will fly over to watch because it would only be right. He may pop into the All England Club this week and would like to play a practice set there one day. It can hardly turn him down.

He says that Andy Murray is a legitimate contender for the top and can win the game's finest title. “I would be happy to give him any advice on that he'd like,” Sampras said. “I know a thing or two about it.”