Typically, Borg is the more restrained critic. It would have been fun if the film-makers had involved him and McEnroe, he says, but it's OK. "... OK but still a fiction film."

McEnroe, who has discovered the appeal of self-deprecation in his later years, is more forthright.

They need not have bothered to invent anecdotes that make him look like a jerk, he says. He could have given them plenty of true stories which would have done the job much more efficiently.

Ice-Borg versus Superbrat. It was a match made in showbiz heaven.

Even their hairstyles were at war with one another – Borg's Prince Valiant bob versus the McEnroe frizz. In the weeks before the tournament began, the professional tennis marketing machine was already gearing up to make celebrities of them and their hair.

The casting is inspired. Metz was lucky enough to find a Borg look-alike who can act in lanky Icelandic actor Sverrir Gudnason and Shia LaBeouf, a Hollywood favourite when it comes to cocky characters, makes McEnroe convincingly obnoxious – although it is a one-dimensional performance. If there is another side to him, we don't see it.

The action covers the weeks leading up to Wimbledon. Then it races through the preliminary rounds in its haste to get to the main event.

En route, Borg does rather too much brooding in close-up while Stellan Skarsgard, who's never been better, tackles the unenviable task of reassuring and revving him up. He plays Borg's coach, Lennart Bergelin, who takes him on as a teenager, nursing him through his angry years and helping him harden into Ice-Borg.

However, he can do little to relieve the anxiety attacks that overtake him at the prospect of meeting McEnroe at Wimbledon after losing to him twice before. Borg is still No. 1 but he's haunted by the thought that the end is in sight.

Most of it rings true but I think McEnroe is right. There's a juicier story in there somewhere.