Both retailers beat expectations for the key festive period as overall food prices remain high.
Retail giants Tesco and Marks & Spencer have both reported stronger-than-expected sales for the key Christmas trading season.
Tesco said UK like-for-like sales – which strip out the impact of new stores – rose 6.8% over the six weeks to 6 January.
The supermarket giant also raised its profit forecast for the full year.
M&S also reported robust demand for the festive period, especially in its food business.
Sales rose 8.1% over the 13 weeks to 30 December, with M&S saying womenswear was the “standout” performer outside of its grocery division.
The past year has seen big rises in food prices, which has pushed up the value of sales at all supermarkets.
However, M&S warned of an “uncertain” outlook for this year, “with consumer and geopolitical risks”.
“We also face additional cost increases from higher than anticipated wage and business rates related cost inflation,” the company added.
Tesco said it had seen growth in sales volumes, as well as sales values, and that it continued to outperform the wider market.
It saw strong sales of premium food products, with sales of its Finest range sales up by nearly 17% over the Christmas period.
At the same time, Tesco said it had cut prices on nearly 2,700 products as sought to head off competition from discount rivals such as Aldi and Lidl.
The supermarket now expects its retail operating profits to hit £2.75bn for the full year, above its previous guidance range of £2.6bn to £2.7bn.