The like-for-like sales figures for the 12 weeks to Boxing Day beat the forecasts of City analysts who had predicted a 3.5 per cent gain.
The data also show that excluding fuel and the change in VAT, sales climbed 4.2 per cent.
Sainsbury’s, Britain's third largest supermarket chain, slashed prices on its beer wine and spirits in a bid to bring more customers through the door.
Chief executive Justin King said Sainsbury's had delivered a “record performance”.
He added: "While food price inflation eased in the quarter as expected, a winning combination of more customers, enjoying even better products and prices through more stores delivered total sales growth of 6.2 per cent."
Nectar customer card data customer revealed that 14 per cent more customers bought their turkey and trimmings from Sainsbury’s than last year.
On the year ahead King said: "The business continues to perform well in what remains a challenging consumer environment.
"Our universal customer appeal together with our accelerated growth plans means we are well placed to make continued good progress in 2010."
Data from research firm Nielsen suggested the supermarket had increased its market share by two percentage points to 14.7 per cent with the Christmas sales hike.