Department store retailer John Lewis unveiled a 36% year-on-year sales increase in the week before Christmas.
The seven-day period ending Christmas Eve, which included two extra trading days compared with the equivalent week in 2015, generated sales of £175.6m.
The retailer said household items were particularly popular online in the run up to Christmas, and click-and-collect orders were up 15.9%.
However, sales the following week, during which its clearance Sale began, slid 9.4% to £138.5m.
The retailer put this down to the week to December 31 including both Christmas day and Boxing Day, when its department stores were closed.
The equivalent week last year included only one day when its shops did not trade – New Year’s Day.
In the week after Christmas, best-selling products online from the retailer’s clearance Sale included Mulberry handbags, Dyson vacuum cleaners and beauty gift sets.
It said the busiest day in-store was December 27, as customers sought bargains after John Lewis stores re-opened.
Sales in its electricals and home technology category were down 13% year on year, while sales in its home department dropped 12.5%.
Upmarket grocer Waitrose said its sales in the seven days to Christmas Eve were up 31% year-on-year.
It put this down to two extra trading days, compared with last year.
Waitrose was also closed for two full days in the following week, however, when sales fell 12.5% to £109.7m.
The grocer said entertaining was a key theme throughout the two-week period, with sales of party food up 14% and slow cooked meats surging 63%.
Sales of English sparkling wine rocketed 65% in the run-up to New Year’s Eve, with champagne also up 13%.