Upmarket supermarket Waitrose has continued to outperform the under-pressure grocery sector after figures showed a lift in Christmas sales.

The John Lewis Partnership-owned chain said like-for-like sales for the five weeks to January 3 rose 2.8% compared to a year ago, while total revenues for the period rose 7% to £728million.

The employee-owned firm, which has 334 stores, said grocery sales through Waitrose.com jumped 26.3%.

Brokers forecast that none of Waitrose’s big four rivals – Tesco, Asda, Sainsbury’s and Morrisons – will post like-for-like sales rises over the Christmas period.

Waitrose is one of the winners of the ongoing supermarket price wars that has seen the big four grocers squeezed between premium grocers at one end and discounters such as Aldi and Lidl at the other.

Analysts expect the food business of upmarket Marks & Spencer to report same store sales rise of 0.9% over the Christmas period.

Waitrose managing director Mark Price called the retailer’s figures a “strong sales performance in a tough trading environment”.

He added: “As a business owned by the people who work here, we can take the long-term view and our Christmas results show the effectiveness of our strategy of investing in good value, in making our shops attractive destinations and in building our online business.”

Shore Capital analyst Clive Black said: “We believe that Waitrose’s performance will stand up very well against the superstore groups and will probably exceed the sales momentum of Marks & Spencer too.”

“All credit should go to Waitrose for cranking out such a robust performance to our opinion.”

Waitrose has been steadily improving its performance over the last year, and now has around a 5% of the UK grocery market.

Neil Saunders, managing director of retail consultancy Conlumino, said: “In the battleground that is the grocery market, Waitrose has emerged as a clear winner over the festive period.”

The retailer added it plans to close a warehouse in Acton, west London as the site was “almost certainly” going to be the subject of a compulsory purchase order for the High Speed 2 rail project in 2017.

But it added it was building another warehouse to cater for online orders at Coulsdon, south London, which at 80,000 sq ft will be more than twice as big as the west London plant.

Waitrose said this site would employ 450 staff and it was consulting with workers at the Acton warehouse to either employ them at the new plant or at nearby stores.