Bridesmaids, Paul Feig, 124 mins (15)

It's got the rudery and crudery, but this is also a sassy, smart comedy where the women are competent and it's the sugared almonds that get skewered

For a moment in US comedy Bridesmaids, your heart sinks.

A bride-to-be and her friends decide on Las Vegas for their hen party. You can see the routine slump that this promising film is heading into – oh yes, we really needed "The Hangover: Ladies' Night". But that would have been far too easy. As it happens, Bridesmaids never reaches Las Vegas – and the reason comes in a superb extended sequence, the old disorderly-on-a-plane routine given new fizz, and unlikely poise, by the film's elegantly manic star and co-writer Kristen Wiig.

Widely hailed as a refreshing deviation from the norm, Bridesmaids brings acerbic adult wit to the tired, often infantilising genre of the Hollywood women's comedy. It's produced by Judd Apatow, but where his films as director or producer tend to make wives and girlfriends second-stringers to male traumas, Bridesmaids puts women, their woes and their wit at the centre. The director is Paul Feig, but its real auteurs are Wiig and her co-writer Annie Mumolo.

Wiig is a protean Saturday Night Live regular, whom British viewers will remember as a sour-mouthed television executive in Knocked Up. More likeable here, Wiig plays Annie, whose best friend Lillian (Maya Rudolph) asks her to be maid of honour at her wedding. Then along comes wealthy, elegant, hyper-confident Helen (Rose Byrne), who promptly usurps Annie's role. The bridal shower that Helen arranges – with its chocolate fountain, mock-Parisian trimmings and swans – is a nightmare of tweeness, and we can only share Annie's enraged horror at this glutinous farrago.

For all the fluffy trimmings, this is hardly a romcom, despite Annie's comic romance with an affable cop – a gruff, teddy-bearish Chris O'Dowd. Nor is it strictly a wedding comedy – that peculiar sub-genre that revived with the boisterous Muriel's Wedding before spawning countless insipid variants. Bridemaids cheerfully skewers such films, and in particular targets the retrograde cult of cuteness, the notion that pastel pinks and sugared almonds are – even in a, you know, ironic way – what every woman wants.

For a contemporary Hollywood comedy, Bridesmaids is exceptionally classy, and very confidently paced. Early on, Annie and Helen, with increasing gritted-teeth sincerity, try to outdo each other making speeches in Lillian's honour. The routine is spun out to the point at which it's almost not funny any more – which is precisely why it ends up even funnier, because Wiig and co aren't afraid to go beyond the point of obvious good proportion.

At one point, the film does go for the easy option: Lillian and friends visit a chi-chi bridal salon, only to be savagely hit by food poisoning. This was Apatow's idea, apparently – if anything will lure men into a chick flick, it's diarrhoea – but the broadness seriously jars with the rest. And yet the sequence has two grace notes: a gut-stricken Lillian in full bridal white, flopping in the street like a deflating balloon, an image not just funny but bizarrely poetic; and Annie, ashen-faced and dripping with sweat, refusing to admit that there's anything wrong.

In fact, the most acute comedy here is consistently about Annie's attempts to maintain dignity in the face of everyday humiliation. Wiig depicts Annie's constantly imperiled sangfroid with magnificent style, whether she's out to convince O'Dowd's cop that she's sober – goofily dancing on skewed pipe-cleaner legs – or subsiding into the grip of flight-phobia panic.

One reason why the film has hit a chord with female audiences is Annie's approachable, ordinary neurosis. The film doesn't present her as a hopeless self-deprecating Bridget Jones-y mess – nor does it play that disingenuous trick of persuading us that a poised, attractive, intelligent actress (Tina Fey, say, in 30 Rock) is a hopeless dork with a doomed love life. Annie is anything but inept, she's just fallen on standard hard times: she lost her shirt on a failed cake shop, and now she's living with appalling flatmates (Matt Lucas and Rebel Wilson as an oddball sibling pair, rather seeming like another Apatow bolt-on). Wiig's subliminally frazzled composure is magnificent throughout, with a constant undertone of tightly flexed anxiety beneath the groomed lanky beauty.

The film makes some of the expected points about What Women Really Think – e.g. about the sort of bad lover played here by Jon Hamm. But what gives Bridesmaids its edge is the easy conspiratorial feel, the collusive rhythms between Wiig and her co-stars. There's a wonderful improv-style looseness in the riffing between Wiig and Rudolph, and a terrific tautness in Wiig's scenes with Byrne – who gamely sends herself up as a hygienically bland goddess. Melissa McCarthy as Megan consistently steals the show with her bluff strangeness, resembling a dementedly babbling female Ricky Gervais stepping into Roseanne Barr's tough-girl shoes. The recently deceased Jill Clayburgh, as Annie's eccentric mother, also weighs in with a few choice salty one-liners.

Unashamedly smart, in a way that's widely permitted on US television but almost never in the movies, Bridesmaids has been hailed as a groundbreaking blow for American female cinema. That says a lot about the extent of Hollywood's current conservatism, but for now, Bridesmaids does nicely as a tonic corrective. Men will love it too, although some of us may need the anal bleaching jokes explained.

Next Week:

Jonathan Romney samples divorce Iranian style, in Berlin prizewinner A Separation