After Michael Chang defeated Pete Sampras, Jim Courier and Andre Agassi in a Champions Tour final in Washington last week the post-match conversation turned to the prominent role of the physio in the tennis senior circuit.
"Andre's got the bad hip. My back's always been stiff," Sampras told the Associated Press. "The trainer, he's the most important guy on the tour."
Fans are rightly impressed that Chang, 39; Sampras, 40; Courier, 41; and Agassi, 41, still can play tennis of quality; the proof is in the money they pay to watch them.
What, then, to make of Thomas Muster, the 44-year-old Austrian?
Muster, a former world No 1 and the 1995 French Open champion, returned to competitive tennis last year after an 11-year absence. He not only made regular forays into Champions events, three times he ventured into ATP tournaments, where 30 is considered old and 40 hopelessly creaky.
Muster has failed to win any of the three matches he played, but he was competitive in two, against players ranked in the top 200.
Now, Muster has said it is time to give up competing against men less than half his age.
He said the Erste Bank Open in Vienna next month will be his last tournament; he has been awarded a wild card into the main draw.
"I wanted to relive competitive tennis again and I've really enjoyed it," Muster said in Vienna last week. "I've made good progress this year but my age is counting.
"For me, I know what's still possible if I put even more effort into it. But I have a family and also would get to my physical limits one day."
Muster was known as the King of Clay during his heyday; 40 of the 44 career titles he won came on the surface. He was No 1 for six weeks in 1996, when he was 28.
In 1999, after losing in the first round of the French Open at age 32, he announced he was taking "a break" from the game. The break stretched over more than a decade.
His first ATP match back was a year ago in Vienna, a 6-2, 7-6 defeat to Andreas Haider-Maurer, ranked No 157. He lost to Sergei Bubka 6-1, 4-6, 6-4 in a qualifier for the Halle tournament. Only at Kitzbuhel, where he lost to No 43 Philipp Kohlschreiber 6-3, 6-0 did Muster seem overmatched. As competitive as Chang, Sampras, Courier and Agassi remain, none of them operate under the illusion they could trade shots with active Tour players.
Muster realises it is time to go. Again. "You should not drag it along forever," he said.