McEnroe loses opener - and temper
John McEnroe was easily beaten by Henri Leconte 6-4 6-4 at the Honda Challenge in London on Wednesday.
McEnroe, who had beaten the Frenchman in both the 1997 and 1999 London finals, may have lacked form but he showed he had lost none of his temper.
He destroyed a section of court banners and escaped warnings from umpire Jeremy Shales for bad language.
McEnroe said: "I've lost to Leconte two out of 31 times, so I wasn't thinking I was going to lose the match."
McEnroe has one last chance to stay in the tournament.
In Thursday's second match of the round-robin stage he faces Swede Mikael Pernfors, who was brought in at the last minute to replace the injured Boris Becker.
"It's a wake up call, and I know I'm out of it if I lose the next match," added McEnroe.
"I still have a chance. But there's no doubt I will be if I play like that - my days are numbered."
Earlier, Australian Pat Cash won a close encounter with Sweden's Mats Wilander.
Cash served and volleyed his way to a 7-6 (7/4) 7-6 (7/4) victory as he was reminded of previous meetings on the main tour.
"I think Lleyton Hewitt is a new version of Mats Wilander - they play very, very similar tennis. I think Mats has probably got a better serve," said Cash.
"Especially when he starts passing me like the way he did today it seriously brought it back.
"He's quite incredible how he can still do that. I don't know how many matches he's played - but I hit some unbelievable volleys and approach shots."
In the other singles match of the afternoon session Petr Korda, last year's beaten finalist from the Czech Republic, beat former British number one Jeremy Bates 6-4 6-2.