Chief executive Steve Rowe said that consumers were "definitely facing a squeeze on spending" as the retailer posted a 1.4pc fall in group like-for-like sales over the 13 weeks to December 30.
Close rival Debenhams warned over profits last week after tough trading, while figures also out on Thursday from Marks & Spencer showed a steep fall in clothing and home sales, although it blamed this on an unusually warm October.
This helped to grow its share of turkey sales over Christmas, when more shoppers bought their main meat meal from Sainsbury's, according to the retailer.
M&S says it adhered to its full price stance despite the promotional nature of the period, and did not participate in Black Friday.
He said that but for October's unseasonable mild weather, M&S would have had a positive sales performance for clothing.More news: Vivo unveils first smartphone with in-display fingerprint scanner
M&S also carried more stock into its December sale.
Alongside the Christmas update, Tesco reported a 2.3% rise in sales for the third quarter, just before the festive period, meaning that for the combined 19 weeks it was up by 2.1%. As was the case in November, it is now in danger of establishing an unwelcome position below the 300p threshold - a key level of technical support - for the first time since 2008. Total sales in United Kingdom however improved 1.1 percent to 2,858 million pounds (3,855 million dollars), while like-for-like sales decreased 1.4 percent in the quarter.
Same store food sales fell 0.4 percent - better than analysts' average forecast of a 1.1 percent decline but worse than a 0.1 percent fall in the previous quarter.
Global sales during the quarter declined 9.8 percent to 309 million pounds (416.6 million dollars), while M&S.com sales of 309 million pounds improved 3 percent.
That trend was confirmed today by John Lewis (JLH) Partnership chairman Sir Charlie Mayfield, who said pressure on margins at John Lewis and Waitrose had intensified in recent months "because of our choice to maintain competitive prices". The engineering firm said that changes in US taxes will result in a one-off non-cash tax credit for 2017. Such an outcome would be a second straight year of decline.