It said growth was most marked in online with sales up 48.5% for the quarter as a whole [13 weeks ending May 30] and rate of growth increasing to almost 100% by the end of May.
Following today's release of Tesco Q1 figures for 2020/21, Thomas Brereton, retail analyst at GlobalData, a leading data and analytics company, comments: "With non-retail food options cut off, consumers have shifted spend to supermarkets at an unprecedented level over the past three months, and, with its national prominence, Tesco has been the first port of call for many".
In a trading update, Tesco said group sales had risen 8% to £13.4bn in the period, but warned coronavirus-related costs were set to hit £840m this year.
In a statement the company said: "Responding to the significantly increased demand for our online offer, we have grown that part of our business as quickly as possible".
The retailer is now delivering more than 1.3 million online orders per week, with a total of 12.6 million filled during the first quarter.
Tesco said its Irish like for like sales jumped by 20.5% to £697m, while its United Kingdom sales increased by 8.7% to £9.912 billion. In total, our latest estimate of incremental costs for the United Kingdom for the full year is approximately £840 million.
Tesco, however, said fresh costs had including paid leave for vulnerable staff, hiring temporary staff to meet extra demand and purchasing safety-related consumables and personal protective equipment.
For convenience its UK Tesco Express and One Stop businesses grew by 9.9% over the period while its Booker retail partners (Premier, Londis, Budgens) saw growth of 23.5%.
AJ Bell investment director Russ Mould thinks Tesco's efforts during the pandemic so far in increasing online deliveries, ensuring it keeps shelves stocked with items people need, and providing employment to people who've suddenly found themselves out of work, could result in greater customer loyalty down the line.
Tesco's latest estimate of incremental costs from the crisis was 840 million pounds, partly offset by business rates relief and increased sales.
"Investors should keep a close eye on the company, since the group operates in a crowded market with retailers Aldi and Lidl continuing to gain market share and current results might not be replicated when the United Kingdom is lifted from lockdown", he said.