It's not often that Sportin' Life is upstaged but, in Cape Town Opera's production of Porgy and Bess, it happens when Sportin' Life (Tshepo Moagi) tells us 'It ain' necessarily so'. The orchestra, formed in association with Welsh National Opera and conducted by Albert Horne, delivers a tight rendition, with rippling banjo from Daniel Thomas and blaring trumpet from Manda Mlangeni.

Designer Michael Mitchell's Catfish Row is propped up with scaffolding and relocated by director Christine Crouse to 1970s South Africa. Largely, it works well, from Philisa Sibeko's first soaring notes of 'Summertime' to the uplifting final chorus, by way of some lively song-and-dance numbers from choreographer Sibonakaliso Ndaba.

The love story plays out against a background of respectable poverty versus drug-dealing and mindless violence. Xolela Sixaba is a rich-voiced Porgy, propelling himself around the stage on his board with castors. There is little self-pity in him and a lot of humanity. When the thug Crown stabs Robbins in a petty fight and flees, he leaves his woman Bess behind. Porgy is the only one to take her in.

Tsakane Valentine Maswanganyi is a gloriously Technicolor Bess. When she first appears, as Crown's moll, openly drinking from a bottle in the street, she scandalises the respectable women of Catfish Row. In tight blouse tucked into short skirt and boots on legs that, in the vulgar phrase, go all the way up to her bum, this woman is dangerous. And traditionally-built Miranda Tini, as Maria, has no hesitation in telling him so.

In their duet 'Bess, you is my woman now' Maswanganyi is more operatic and restrained than the relaxed delivery of Sixaba but has loosened up by her second duet with Porgy - "I loves you, Porgy".

Sportin' Life' attempts to woo her back onto drugs and the train to New York. Instead, on the church picnic to Kittiwah Island, she is detained by Crown (Ntobeko Rwanqa), who has been hiding there and, having had enough of birds' eggs and oysters, is hungry for his woman Bess.

Rwanga is a forceful Crown, dominating the community of Catfish Row with his size as he dominates Bess. His casual, drunken assaults and taunts are not redeemed by his venturing into the hurricane after Clara (Philisa Sibeko), who has rushed out into the storm hoping to rescue her fisherman husband Jake (Aubrey Lodewyk). There is none of the outpouring of grief when he is killed as there is for Robbins, or Clara and Jake.

And the outpourings are that indeed. This is no polite 'operatic' chorus but one which raises its collective voice to celebrate its collective faith in a better afterlife with a fervour and conviction that Sportin' Life's cynicism cannot destroy.

During Porgy's imprisonment, Sportin' Life hooks Bess back on the happy dus' and, in the vibrant 'There's a Boat Dat's Leavin' Soon for New York', Bess changes from the simple print frock of Catfish Row into the tight blouse, skirt and boots and leaves with him. When Porgy returns, despite the ludicrousness of his following Bess, we cheer him on his way.