The retailer kept operating some stores during the lockdown, with like-for-like revenues jumping 22% in the eight weeks to 23 May thanks to high demand for gardening and DIY products.
Demand was boosted by warm dry weather and customers being at home during the lockdown as well as the closure of other DIY and gardening retailers.
Excluding those two categories, sales were up 10%.
The FTSE 250-listed firm, which has also reopened most stores in France, said operating costs have been higher due to social distancing measures and the payment of premium wage rates during the COVID-19 peak period.
The last quarter in the year to 28 March saw revenues rising 6%.
Peel Hunt raised the target price to 500p from 450p on the back of the "sensational" results.
The full-year profit forecast was revised up to £450mln from £388mln, implying a slowdown in the second half.
"We consider it a remarkable performance given that transaction count is sharply down: shoppers clearly mean serious business when they leave lockdown," analysts commented.
Liberum also resumed its 'buy' recommendation from under review, with 425p target price.
"The group’s position within the UK discounter space remains a good place to be, especially if the consumer and economic bounce back takes some time," analysts commented.
Shares advanced 4% to 383.1p on Friday at the opening bell.
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