Tennis-based biopics are like buses – you wait years for one to come along, and then two premiere at TIFF in the same week. This autumn on centre court two tales of fierce sporting rivalry are playing out: Battle of the Sexes, starring Steve Carrell as Bobby Riggs and Emma Stone as Billie-Jean King, and Borg/McEnroe, starring Sverrir Gudnason as Björn Borg and Shia LaBeouf as John McEnroe. With the Borg/McEnroe story already lampooned by Jake Szymanski’s 2015 mockumentary 7 Days in Hell, Janus Metz Pedersen approaches one of sport’s most famous rivalries with an altogether less playful tone.

The film focuses on the weeks leading up until Borg and McEnroe’s legendary meeting in the 1980 Wimbledon final, although it spends a decent amount of time establishing a dramatic backstory about Borg too, flashing back to his childhood as a promising but undisciplined student under the tutelage of aging tennis star Lennart Bergelin – played by Stellan Skarsgård (who might be contractually obliged to appear in every film about his home country).

Substantially less is seen of John McEnroe, who is afforded far less screen time than his Swedish rival, which makes the title somewhat misleading – interestingly in Sweden, the film is being released solely under the name ‘Borg’, which seems more accurate. There are a couple of McEnroe flashbacks thrown into the mix, but they feel perfunctory, and there’s a distinct impression that Swedish screenwriter Ronnie Sandahl might have had a vested interest when he wrote the script.

This is particularly unfortunate given the fact that Shia LaBeouf is the most compelling thing about the film. He portrays McEnroe as a ticking time bomb primed for detonation, capturing the manic outbursts that made McEnroe a pantomime villain on-court, and yet bringing to a role a sense of vulnerability and desperation. It would have been easy to play McEnroe as the enemy, but LaBeouf’s performance is nuanced and captivating – it’s a shame there’s just not more of it.

Meanwhile, Sverrir Gudnason wins points for his striking resemblance to the real-life Björn Borg, but his performance is underwhelming and almost sedated. Whilst this might be in keeping with the film’s narrative, which pits Borg as the quiet, controlled party against McEnroe’s enfant terrible, is does make him rather boring to watch. It is only through flashbacks that we are given any insight into his character, and there’s not much incentive to root for his success, either.

The action on-court is something to behold – a blisteringly tense rendering of the match manages to keep you on your toes, though there’s no reason given for McEnroe’s change of attitude when he reaches the finale, and the film really needs that to fulfill the redemptive arc it attempts to establish.

Much like a long game of tennis, Borg/McEnroe is frustrating to watch – a case of missed opportunities, with rare flashes of brilliance, but a grand slam is never forthcoming. Great wigs though; I’ll say that much.