Sales at Boots collapsed by almost a third in the three months to August as shoppers shunned city centres, train stations and airports.
Like-for-like retail sales plunged by 29.2pc compared to a year earlier, even though the chemist chain kept swathes of its stores open at the height of the Covid crisis. Overall UK sales fell 16.7pc.
Britons have remained reluctant to return to shops even though the restrictions have largely eased. Shopper numbers were still down 31pc year-on-year this week, fresh data showed.
Boots said the performance was an improvement on the previous quarter when like-for-like sales fell by 48pc. It also said that it kept most of its branches open at the peak of the crisis even though this was costly.
The firm is among several retailers to withheld rent payments from landlords for some stores. It claims its outlets should be treated similarly to those forced to shut at the height of the lockdown as footfall collapsed, many of which have refused to pay their bills.
The Nottingham-based chemist has become a thorn in the side of its US owner Walgreen Boots Alliance , which in July said it would write off $2bn (£1.5bn) of value from Boots.
On Thursday, Walgreens' international pharmacy retail division posted a $132m (£102m) quarterly operating loss that it said was mostly driven by lower sales in the UK.
The chemist is cutting more than 4,000 jobs – about 7pc of its workforce – and shutting 48 optician branches.
Its parent company said one of its priorities was to speed up the turnaround of Boots, which has lost market share in all of its categories other than beauty in the quarter.
However, it hailed strong online sales as Boots.com reported 155pc growth, following a 78pc increase in the previous quarter.
Boots has been doubling down on beauty under its UK boss Sebastian James, and has begun selling major brands such as Laura Mercier, Nars, MAC, KVT, Revolution XX and Philip Kingsley.
Mr James was appointed managing director two years ago after a four-year tenure as chief executive of Dixons Carphone.
The chain, which traces its roots to John Boot’s first Nottingham store in 1849, employs more than 50,000 people.
It has provided a million Covid-19 tests for Britons since the outbreak took hold, helping the Government broaden testing.
In February last year it said it would cut 350 roles at its Nottingham office.
Walgreens chief executive Stefano Pessina, who is stepping down to become executive chairman, said: "Despite uncertainty amid the global Covid-19 pandemic, we are seeing gradual improvement in key US and UK markets and continued strong performance in our wholesale business. I'm also encouraged by the accelerating growth in our e-commerce platforms.
"Now, more than ever, our pharmacy-centred business is at the heart of community healthcare and we are expanding on that role for the future."
Overall sales rose to $34.75bn from $33.95bn at the group, while profits fell to $373m from $677m.
Shares in Walgreens Boots Alliance rose 3.5pc in New York to $37.17. They began the year at $59.