Other former Grand Slam champions in the field are Mats Wilander, Pat Cash, last year's runner-up Thomas Muster and, for the first time in London, Spain's Sergi Bruguera, while home interest comes in the shape of British Davis Cup captain Jeremy Bates, one of the two wild cards - Henri Leconte is the other.
The eye-opening progress of his home nation, Croatia, to this week's Davis Cup final has meant Goran Ivanisevic, the 2001 Wimbledon champion, giving up his place at the London finale after comfortably topping the qualifiers by winning three senior tournaments during 2005. Ever the romantic, the 34-year-old Goran is off to Bratislava to help his beloved homeland take on Slovakia in a confrontation between perhaps the two least-fancied finalists in the long history of the competition, and hoping to get a game while he's there.
If this seems unlikely, it is partly Ivanisevic's fault, since his eccentric brilliance has so inspired Croatia's wannabes that Ivan Ljubicic, Mario Ancic and the towering Ivo Karlovic are now ATP Tour stars. Perhaps, if they do well in Friday's opening singles matches, Croatia's captain Nikki Pilic will pitch Ivanisevic into the doubles.
Ivanisevic reckons he is playing better now than when he reached the third round of the 2004 Wimbledon, his farewell to the pro tour. "Having qualified for the Masters, I would have loved to play at the Albert Hall because I heard it has an unbelievable atmosphere and I think I would have had a real chance to win. But it is the chance of a lifetime for me to be in the Croatian team for the Davis Cup final. But trust me, I will be in London next year."
Both Courier and McEnroe agree that Goran and his mighty serve would have been favourite on the arena's fast carpet. In his absence, McEnroe, never noticeably short of confidence or, at the age of 46, enduring skills, thinks he can add to his Masters victories of 1997, 1998, 1999 and 2003. McEnroe finished second on the qualifying list after wins in Frankfurt and the Algarve.
"I'm getting myself really pumped up for this one," he promised. "It's the senior event that's been around the longest. It's the most beautiful venue and there's an opportunity to win a nice bonus of a hundred grand. That's enough reasons to try to end the year in style."
However, Courier looks the one likeliest to scoop that bonus, as he did last year on his debut at senior level. The man who won the Australian and French Opens twice each, recalls last December's triumph as one of his most memorable.
"Fantastic, it capped my first year on the seniors, and it underlined that I was back and playing well after my injuries," said Courier. "Very rewarding."
In fact, he was so impressed by what he saw on the European seniors' tour that he has started one in the United States through his New York company, Inside Out Sports and Entertainment.
He won the only American tournament so far, in Houston last month, beating Todd Martin 6-2 6-3 in the final. "That was the best tennis I have played in a long time," said Courier, "and it was against someone who has only just retired from the main pro tour. The competition in the seniors is getting better, deeper and tougher all the time and that's the ultimate attraction of it.
"The Albert Hall is a building that supersedes what is playing there, but you have to have something great going on, otherwise you just go to see the Albert Hall and never go back again.
"This needs to be legitimate competition for people to continue to want to come back. With the names we have, it is clear that hit-and-giggle tennis is a thing of the past."
With Mansour Bahrami and Ilie Nastase among the participants in the accompanying doubles event, a giggle or two is certain still to be available, but the measure of commitment among the singles brigade was evident at the qualifying event in Essen last month, when Cash and Muster almost came to blows after one fiery contest.
The Masters round-robin stages from Tuesday to Thursday will eliminate one from each of the four groups before the knock-out begins with the quarter-finals on Friday.
The draw: Group A: John McEnroe, Sergi Bruguera, Mikael Pernfors. Group B: Thomas Muster, Paul Haarhuis, Jeremy Bates. Group C: Cedric Pioline, Pat Cash, Henri Leconte. Group D: Jim Courier, Anders Jarryd, Mats Wilander.Reuse content