She deserved a standing ovation simply for surviving two hours on-stage. Liza Minnelli has endured so many personal crises that she has begun to make her late mother appear a model of decorum. Thankfully, the singer is still capable of laughing at herself. This evening – the start of her British tour – was peppered with wry references to discarded husbands, weight problems and her inability to get through the first half without resting in a chair.

In the end, her adoring audience gave her a good half-a-dozen ovations. Never mind that her voice was often ragged, and that the second half of the show wandered all over the place. What matters to Minnelli’s fans – sedate, middle-aged ladies and hyperventilating gay men alike – is that she still embodies every showbiz legend under the sun. After decades in the spotlight, her life has become the grandest Broadway musical of them all.

If she struggled to hit notes, she nevertheless looked marvellous. The excess pounds had miraculously vanished, and after a costume change during the interval she flashed a pair of impressively sleek legs. Although her movements were often tentative, Minnelli – now 62 and the recipient of a couple of artificial hips - bore a striking resemblance to the disco queen of the 1970s.

She was in retrospective mood for much of the evening, paying homage to her muses, Kander & Ebb, creators of “Cabaret”, and devoting most of the second half to a long tribute to her godmother, that larger than life performer and vocal arranger Kay Thompson. This part of the show was obviously a labour of love. But the long-winded re-creation of Thompson’s nightclub act featuring four male dancers, dressed like execs from “Mad Men”, who impersonated The Williams Brothers (a launchpad for the young Andy Williams) won a lukewarm response. As did Minnelli’s brief paean of praise to Nancy Reagan in the first half. Memo to visiting American stars: Ron and his First Lady are not quite royalty over here.

Still, “New York, New York” - which Thompson helped Minnelli to master - was dispatched with genuine class. And the good news about the post-interval performance was that the sound quality had markedly improved. For the first hour, it had been nothing less than atrocious, Minnelli’s mike dripping with reverb as she struggled to make herself heard above an over-amplified 12-piece band featuring her long-time collaborator, the pianist Billy Stritch.

Minnelli, who also seemed to be struggling with a cold, fought her way through nevertheless, performing “Maybe This Time” while seated and bringing a touch of vulnerability to “My Own Best Friend”, one of the more heartfelt numbers from the score of “Chicago”. Her audience, eager to be her best friends, helped carry her through the evening. By the end, she looked drained but triumphant.

London residency ends May 27. Tour continues at the Royal Concert Hall, Nottingham on Friday.

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