It's true. Miracles do happen. At an age when he should be putting his well-shod feet up Woody Allen has made his best film in years. I didn't think it was possible but Blue Jasmine, which has been receiving rave reviews in America and has already created an Oscar buzz for its star Cate Blanchett, really is a return to form. Of sorts, that is. 

I've only got one problem. It's not as funny as I hoped. In fact I'm not sure if it can be classified as a comedy at all. Of course there are some terrific lines in it, but they are sprinkled through the script like gold dust rather than carpet bombed over the whole 98 minutes. You will smile during Blue Jasmine, and be reminded of great past Woody Allen films, but this is also a very serious, mature movie, light years away from the nadir of his "wilderness" years, Cassandra's Dream (2007). I should disclose here that I have a soft spot for Scoop (2006), which I don't think even had a UK cinema release, in which Allen played a fumbling magician who could have been a client of Broadway Danny Rose (1984).

Blanchett plays the titular lead, who heads to San Francisco following the death of her disgraced banker husband (Alec Baldwin, flashbacks slowly and cleverly reveal her past). Jasmine is broke but still trying to live the life of an upper class Manhattanite, flying first class and generally behaving as if she is on top of things, when it swiftly becomes clear she is anything but. She babbles to strangers, pops pills and knocks back vodka like it is going out of style. She clearly suffers from delusions, thinking she is going to retrain as an interior designer when she can barely get to grips with her new part-time job as a dental receptionist.

While in San Francisco, Jasmine stays with her easy-going sister, Ginger (Sally Hawkins). They were both adopted and have different biological parents and are, not surprisingly, chalk and cheese. Ginger it emerges, broke up with her partner Augie after a business deal with Jasmine's husband went pear-shaped. Jasmine's relationship with Ginger is a fragile one, made all the more delicate by Ginger's brutish but caring boyfriend Chili (Bobby Cannavale). One of the funniest scenes is when Chili tries to fix snobbish Jasmine up on a blind date with one of his check-shorted chums.

Fans of American theatre may spot echoes of A Streetcar Named Desire here in the classy woman fallen on hard times and turning to her family, but as far as I can tell Allen did not set out to make a modern adaptation of the Tennessee Williams play. Although he must be aware of it - he played Blanche Dubious himself in a scene which sent her high class aspirations up in one of his funniest movies, Sleeper.

Blanchett, who coincidentally has played Blanche Dubois onstage, is brilliant and compelling here, dominating every scene she is in. There is not a great deal to laugh at and some of the comedy feels almost unintentional - a fumbled sexual advance boasts the best gag of the film but is also uncomfortable to watch and later there are giggles as a squiffy Jasmine opens her heart to Ginger's bemused children while babysitting.

But if this isn't a laughfest there is still plenty to enjoy. It is good, for instance, to see Allen back in America after his recent patchy films in Paris, Rome and London. While there are some scenes in his beloved New York, most of the action takes place in San Francisco, which feels both fresh and familiar (some of Allen's early films featured the hilly, pretty city too). 

One interesting aspect is Allen's use of comedians. Andrew Dice Clay, who I hadn't heard of since the eighties when he was part of what was dubbed the "comedy of hate" movement (imagine Jerry Sadowitz in more expensive clothes) plays it straight as Augie. And Louis CK pops up too in a role that undercuts his cynical, sour stand-up style. Allen has reportedly said that he would like to work with Louis CK again. Now that's a film I would definitely buy a ticket for.

So where does Blue Jasmine fit into the Allen oeuvre? He can still clearly do comedy. Midnight In Paris was pretty funny when it wasn't being ridiculously sentimental. But maybe in his later years he is finally finding then right balance of seriousness and humour that he was striving for in films such as the Bergmanish Interiors and the Fellini-esque Stardust Memories – the former was too serious for my tastes while the latter was maybe too self-involved, homing in, as it did, on a frustrated film-maker looking back on his career. It is interesting to note the echo of the iconic Manhattan poster in the Blue Jasmine poster above - In Manhattan the lovers were together in the shadow of a famous bridge - here the woman is alone.

2013 has certainly been an interesting year for comebacks. I've often thought of Allen as the David Bowie of cinema. Bowie had a near-perfect run of albums in the seventies and Allen had a similar winning streak including Annie Hall and Manhattan. They both then had their moments in the late eighties but had set such a high benchmark they could never quite match it. Then suddenly this year, out of nowhere, both have come good when, to be honest, one had given up on them. Blue Jasmine is no Annie Hall, but it does show that Allen – like David Bowie – can still deliver. One of cinema's greatest auteurs has apparently already finished his next film, starring Colin Firth. Let's hope Blue Jasmine is no fluke. 

Blue Jasmine is released in the UK on September 27.