Sainsbury's, SuperGroup and Greggs emerged as the winners on Wednesday from a brutal Christmas holiday season for the retail industry.

Britain's third largest grocer was the surprise victor in the supermarket wars: although its stores usually do well at Christmas, the national mood of belt-tightening was expected to hold it back. But Justin King, chief executive, said Sainsbury's had prospered, as shoppers apparently scrimped in October and November to fund a blowout in December: "Customers took the opportunity to spend a little less, week in week out, so they could buy the best for special occasions."

In a sign of the pressure on household budgets, Sainsbury's said shoppers cashed in a record £100m of its Nectar reward points to pay for extras such as champagne and cherry-filled Christmas puddings. Sales of its premium Taste the Difference range were up 10% but sales of its low-price Basics range also rose strongly, as did cooking ingredients, suggesting shoppers were making economies elsewhere – possibly even baking their own Christmas cakes, with sales of unsalted butter and dried fruit up 82% and 30% respectively.

Like-for-like sales at Sainsbury's were up 1.2% excluding VAT in the 14 weeks to 7 January – better than the 0.7% rise from Morrisons and what is expected to be the worst Christmas performance from Tesco in decades when it updates the City on Thursday morning. December data from Kantar Worldpanel showed Sainsbury's market share at 16.7%, its highest since 2003.

"This provides further evidence that the winners this Christmas have been those brands with the ability to fulfil the UK's demand to treat itself on special occasions," said Oriel Securities analyst Jonathan Pritchard.

The downturn has led to an enforced consumer austerity drive: Home shopping group N Brown, whose catalogues include Simply Be and Jacamo, worried investors on Thursday by warning profit margins had been squeezed by discounting and of a rise in the number of bad debtors, sending its shares down more than 5% to 229.8p.

However, baker Greggs struck gold at Christmas as flagging shoppers ducked in to refuel on one of its 30p mince pies. The chain, which now has more British outlets than McDonald's, sold 7.7m mince pies over the festive season. "Our great strength for value hit a chord again for consumers," said its chief executive Ken McMeikan. Like-for-like sales jumped from the 0.8% seen in the third quarter to 5.1% in the five weeks to 7 January, although McMeikan expects growth to be more subdued in 2012.

SuperGroup, the company behind the Superdry fashion brand, also ended a difficult year on a high note with like-for-likes ahead more than 9% in December. Best known for its hoodies, logo T-shirts and neon-check shirts, Superdry issued a profit warning in October after an IT glitch at its warehouse affected stock deliveries to stores. Unlike many rivals, it did not cut its prices before Christmas and chief executive Julian Dunkerton said the strong performance should quiet doubters who have suggested Superdry is getting overexposed. "This has put the nail in the brand conversation," he said.