First thing about Fighting with my Family is that you don’t need to like wrestling, or know anything about it, to find it fun. And it is fun. Writer-director Stephen Merchant sees to that with a sparky script and a slam-dunk cast. It’s based on the true-story of Paige Knight, the first British girl to break into the glitzy world of WWE - World Wrestling Entertainment – from the giddy heights of…Norwich.

The Knight family – mum, dad, brother and sis – teach and perform wrestling in the low-rent backstreets of Britain. But teenage Paige and her older brother Zak long for a shot at the big time with World Wrestling in the USA. When they hear auditions are in the offing, they throw themselves into it, leading to a meet-up with Dwayne ‘The Rock’ Johnson and WWE promoter, Hutch. But when only Paige – and not Zak - is chosen to take part in the Stateside selection programme, it sends bittersweet shockwaves through the family.

Crammed with credible performances, Fighting with my Family skips over the potential pitfalls of cliché. It smacks you with its funny bone for sure. But best of all, it doesn’t pull its dramatic punches – and that’s its strongest move. Nick Frost and Lena Headey are suitably scuzzy and outrageous as the tattooed and potty-mouthed parents, scaring the socks off Zak’s would-be in-laws, and hankering for their own faded glory days. But it’s the relationship between Paige (feisty Florence Pugh, Lady Macbeth) and Zak (an outstanding Jack Lowden, Mary Queen of Scots) that gives the film its grit and good-heartedness.

Starting out as a Channel 4 documentary, the story goes that Dwayne Johnson saw the programme on TV while filming in the UK. Impressed and wanting to produce, The Rock then brought Merchant on board to script and helm. Wise move as Merchant – unlike Richard Curtis – knows how to oomph the drama as well as spin a funny line. Sure, he plunders his pot of penis jokes too often, as if that establishes a working-class world. But he’s not afraid to darken the tone as when Zak kicks off in a pub and his ex-con brother is released from prison.

You may sense how the movie will turn out – and you’d be right. But in getting there Merchant takes the roads less travelled, not saddling Paige with a love interest and pivoting the hinge-point of the film on quiet words from the least-expected source. And while Paige’s edgy bouts against a trio of glamour girls looks destined to end in friendships, it still plays out like a smack on the nose.

Add in a superb, layered turn by Vince Vaughn as the WWE promoter-cum-trainer and you have a film that fires on several cylinders. Yes, it’s a true-life fairy story about being yourself and finding your own way. But trite and twee this isn't. If it has a British film cousin, it’s Brassed Off which also did the light and the dark. But whereas that had a political vibe, Fighting with My Family is much more relatable and inclusive, doing what it says and rooting it in everyone’s family, wrapping it all up in a good-natured, well-choreographed smackdown of a film.

Based on a 2012 Channel 4 documentary, Fighting With My Family follows the Knight family who live, eat and breathe wrestling. When daughter Saraya (who takes the stage name Paige) is picked to join WWE, she must leave her comfortable life in Norwich and fly to Florida. As Paige struggles to make it through a tough training process, her brother deals with rejection at home.

Making his solo cinematic directorial debut (having co-directed Cemetery Junction), Stephen Merchant marshals his film with a deft hand. You expect a script written by Merchant, to be packed with cracking one-liners, and Fighting With My Family duly delivers on this front, with several chortle worthy moments. Yet what makes his work so impressive here is the sweep he gives the film, without ever losing the intimacy that makes it such a surprisingly compelling story. For such a seemingly predictable narrative there is room to explore pressures placed on the female image as well as the fragility of male masculinity and how failure affects this. Fighting With My Family is still mostly a light-hearted underdog story, but its heart is in the right place and its feet are kept firmly on the ground. The journey is hard for Paige and her family, which makes the climax a rewarding one.

Merchant has put together a terrific ensemble for his film. At its centre is Florence Pugh, who continues to produce stellar turn after stellar turn. She is an endearing presence as Paige, skilfully handling both the comedic moments and the more dramatic ones. Jack Lowden gives a suitably compelling performance as the brother struggling to overcome living in his sister's shadow. Nick Frost and Lena Headey make for an appealing duo as Paige's parents, whilst Vince Vaughan is efficiently insulting as Paige's wrestling coach. There's even room for a cameo from Dwayne Johnson (also acting as one of the film's producers) who pops in every so often to steal a scene and lift our heroine's spirits.

Fighting With My Family proves itself an endearing, uplifting sports movie. You'll be able to predict many of the major narrative beats as the film works to its expected ending but Merchant gives himself room to explore unexpected topics. This, alongside another terrific turn from Pugh, manages to elevate the film above other British comedies of recent years. It might not reinvent the sports movie genre but it will cause a smile to emerge on your face as the film reaches its rousing conclusion.