One thing is certain, however: nothing will be resolved over the next two weeks in Paris, whether Muster retains his French Open title or not. He will still, in the eyes of his critics, be a strictly one- surface wonder, and for his own part he will still stand up for his way of doing things.
That surface is clay - the slow red stuff so despaired of by the serve- and-volleyers, so relished by those with a gift, or an appetite, for grinding it out from the baseline. You need stamina to survive on clay, an infinite capacity to charge back and forth and across and engage in rallies of 20, 30, even 40 strokes until one of you can't take it any more. Fitness is paramount, and Muster, by common consent, is the fittest tennis player alive.
For this he is resented. In the macho, preening world of men's tennis, nobody likes to lose out in the physical battle. That isn't an issue in the rat-a-tat game played on grass or indoor surfaces, where the emphasis on explosive power means that few matches come down to tests of mere endurance. But when it's clay underfoot, Muster is the one who is usually left standing after everyone else has collapsed - gasping and begging for mercy.
It is then that Muster's rivals get back at him in the only way they can. They point out that Muster can only play on clay, that clay masks shortcomings that would quickly become apparent if he stepped on to other courts, that he has exploited the ranking system to play tournaments on his favoured surface to the exclusion of almost all others. He may have amassed enough points to have become the world No1 in February - he is No 2 to Sampras at the moment - but it adds up to a false picture, the anti-Musterites claim. There is something wrong with the game, they say, if someone like him can inherit a mantle worn by undisputed greats: Borg, McEnroe, Becker and Edberg.
Given the struggle this lean left-hander has had to get to where he is today, it is amazing the way his many admirers have lost out in the war of words that has raged about his head this year. Born and brought up in the lowland Austrian town of Leibnitz, Muster had few privileges on his way to establishing himself as a young player of immense determination and more skill than history gives him credit for.
He always had a propensity for European clay - that was inevitable given where he learned to play - but he had already reached the semi-final of the Australian Open in 1989 when, a couple of months later, he was involved in the car accident which would have ended lesser men's careers. Muster was loading his kit into the boot of a car in Key Biscayne, Florida, when a drunk driver ran into the vehicle behind him and damaged his left knee so badly it looked as if he might never walk again. The way he fought back is the stuff of tennis legend, and for a long time formed the central part of the Muster story.
Few people realise, perhaps, that the restriction placed on the movement of his left leg as a result of the accident has been an important factor in dictating which surface he plays on. Bending down to the ball, so vital on faster surfaces, matters less on clay, where the bounce is high and there is more time to move into position. So Muster concentrated on what he did best.
Through the early 1990s he was just another solid performer on the circuit - outstanding on clay but not unbeatable. That view of him had to change last year when he began to put together the extraordinary clay-court run that culminated in his beating Michael Chang to win the final of the French, his first Grand Slam title. Between February and June Muster won 40 successive matches on the surface and seven titles. It was an awesome display of power and athleticism, and the success he enjoyed later in the year, notably indoors in Essen, demanded a re-assessment of the limits of his potential.
His form in 1996 has corresponded almost exactly. Before being forced to withdraw injured from last week's event in St Polten, he had won five of the six clay-court tournaments he had entered - in Estoril, Mexico City, Rome, Monte Carlo and Barcelona. Only his semi-final defeat in Munich at the hands of Carlos Moya of Spain suggested he was in any way vulnerable, but the difficulties Agassi and Sampras have had recently suggest that if anyone is going to trouble Muster in Paris it won't be either of them, even though Sampras has been seeded one to Muster's two.
Yet this was the year when Muster, having achieved his goal of a Grand Slam victory, might have finally scaled down operations. "We had a meeting at the end of last year to decide whether Thomas really wanted to go on at the same level," Ronnie Leitgeb, his coach for 12 years, said. "I explained to him that he had reached the point where nothing else counts except success - certainly not financial things."
At 28 - getting on in tennis terms - Muster's response has been unequivocal, involving a redoubling of his commitment to fitness, which any other player, even the super-fit Sampras, would be challenged to match. "Thomas's condition has built up over many years," Leitgeb said. "We always work very consistently on a fitness programme. Twice a year he has a medical check at the University of Salzburg. It's not like other athletes who work for five or six weeks at the beginning of the year and then just play. We never stop. Whether it's match days or practice days we do an hour every morning. Thomas has a basic endurance which is 20 per cent above any other player."
Muster's friendship with the Duchess of York is well-publicised, but he still struggles to earn the respect he surely deserves from his peers. Sampras said he felt it was a wrong system that allowed Muster to reach the top. Agassi accused him of buying points in a supermarket. Muster has responded by pouring scorn on both of them, and Leitgeb doesn't desist either. "I think Agassi's being a bit of a cry baby. I noticed he didn't complain when he got to be No 1."
Muster versus the rest has turned into one of the spikiest contests in the game's history. And for now, at any rate, one of the most one-sided.
Five men aiming to pass Muster
Pete Sampras (US, seeded 1). The death of his coach Tim Gullikson three weeks ago has limited his preparation on clay, which is easily his worst surface. May struggle to live up to seeding.
Andre Agassi (US, 3). After winning the Lipton when Goran Ivanisevic retired early in their final, Agassi has had nagging injuries and played only one clay-court tournament, in Monte Carlo. He lost his second match. The only Grand Slam event he has never won remains, theoretically, the one he is best suited to.
Michael Chang (US, 4). It is seven years since Chang became the youngest ever French Open champion at 17. Has maintained his form since reaching last year's final and will be a handful for anybody.
Marcelo Rios (Chile, 9). First Chilean to get into world's top 10, the 20-year-old Rios is a hugely gifted clay-courter. Pushed Muster to four sets in Barcelona final this year.
Alberto Costa (Sp, 12) At 20, the latest in a long line of outstanding Spaniards. Gave Muster a fright in their five-set quarter-final last year.Reuse content