The Barclays ATP World Tour Finals will begin a new chapter on Sunday as the tournament enters its 40th year. Yet for the inaugural winner, Stan Smith, it seems like only yesterday that he was lifting the title.

Many of the great names of the men's game have had their hands on the season-ending trophy over the decades, but as the competition takes a new direction by making home at London's O2 Arena until at least 2012, Smith is among those eagerly anticipating the action.

The American won the tournament - then known as the Masters Grand Prix - back in 1970 to kick-start a glorious few years of grand slam and Davis Cup success.

As for the competition itself, its prestige continued to grow, and that legacy will continue this week as the world's top eight singles players and top eight doubles teams go head to head until November 29.

The first season-ending championships were played in Tokyo and followed a similar round-robin format to that which is still used. The only difference was that the top six players in the world were involved in one group, and all the players played against one another.

For Smith, his defining moment came in the fourth match-up, as he and Ken Rosewall went head to head for the chance to be crowned champion.

"There's three things that I remember most about that day (December 14)," Smith said. "One, it was my birthday and Jack Kramer came out and orchestrated 10,000 Japanese spectators to sing 'Happy Birthday' to me.

"The second thing was that on the morning of the match with Rosewall I got my final [army] draft notice through the post saying I had to report on December 16 in Los Angeles.

"And finally, it was a very tight match and at the end of it the court was coming up a bit. I think I was up 5-4 and serving for the match, but we had to stop as Rosewall wouldn't play until the court was repaired. After a 10 or 15-minute wait, I returned and had to try to serve it out, which thankfully I was able to do."

Clearly, times have changed, but reflecting on his historic win Smith credits that as the catalyst for the incredible success he enjoyed in subsequent years, which saw him win the US Open (1971) and Wimbledon (1972), as well as enjoying multiple successes in the Davis Cup with the USA.

"Winning the Masters was definitely a big turning point in my career," Smith, now 62, continued.

"It made me realise I could compete against the best players and winning in Tokyo made me feel as though I had a reasonable chance going into any of the grand slams after that. It also showed the best players in the world that I was going to be competitive from then on."

Smith's triumph sees him head a list of tennis greats, and he has subsequently been joined by the likes of Ilie Nastase, John McEnroe, Ivan Lendl, Bjorn Borg, Jimmy Connors, Boris Becker, Andre Agassi, Pete Sampras and Roger Federer, to name but a few.

Such a collection of stars is formidable and, unsurprisingly, Smith feels a certain amount of pride at being amongst that pantheon of greats.

"It was 40 years ago for me, but I know what the guys will feel like," he added. "I think it's a great event to have as the culmination to the year and I know the players really look forward to it. It has become a special event and the players see it as one of the top five tournaments on the circuit.

"Every match will be a great match and I'll be watching again this year. I can't wait."