Tesco has taken aim at the discounters with a campaign promising to lower its prices to match Aldi on "hundreds" of branded and own-label goods online and in store.
The UK's largest supermarket said it would match on price across products including bananas, cucumbers, Warburtons Toastie sliced white bread and other own-label items, giving customers "Tesco products at Aldi prices for simple, great value".
Price-matched items will be identified online and in store by signage showing a distinctive red "Aldi price match" bubble.
Tesco chief customer officer Alessandra Bellini said: "Our customers tell us they want the most competitive prices on the things they buy regularly. This new campaign will help time-poor and budget-savvy customers get Tesco products at Aldi prices on products that matter to them."
According to the latest figures from Kantar, Tesco has 27.2% of the UK grocery market, followed by Sainsbury's, which has 15.6%, and Asda, which has 15.1%.
Aldi and Lidl continue to outpace the growth of their rivals. Aldi, which has 7.9% share of the market, saw sales grow 5.7% in the 12 weeks to 23 February, while Tesco saw sales dip by 0.8%, according to Kantar.