This comes as Tesco emerged as one of the biggest winners in the retail sector over Christmas after sales rose by 9.2% over the four weeks to 25 December, with Tesco hailing a 16.7% increase in sales of its best premium products.
Mr Murphy said the supermarket had seen an increase in the volume of products sold.
Tesco has updated its profit forecasts for this year after strong festive trading. It now expects to generate up to £2.75bn, up from previous forecasts of between £2.6bn and £2.7bn.
Mr Murphy said the retailer had prioritized the launch of 550 new festive products before Christmas.
In a bid to lure shoppers away from discounters Aldi and Lidl, Tesco also cut around 2,700 prices during the period and increased offers across its Clubcard loyalty scheme.
“As part of our focus on value, we offered a full Christmas dinner for just £2.09 per person, which helped drive record sales in the weeks leading up to Christmas and further market share gains,” Murphy said.
He added: “Our commitment to being the cheapest full-line grocer in the country is absolutely firm. That’s what we all are. We’ve been that way for 14 months, and my commitment is that we will continue that way for the foreseeable future.”
Latest data shows Tesco ended the year with a 27.6% share of the grocery market, higher than at the start of 2023 after holding off advances from Aldi and Lidl.
Sales across Tesco’s business – which includes wholesaler Booker’s – rose 6.6% over the 13 weeks to 25 November.
Tesco’s update follows that of rival Sainsbury’s, which recorded an 8.6% increase in food sales over Christmas, highlighting record sales of sparkling wine, mince pies and pigs in blankets.
Sainsbury’s also saw a rise in sales of its premium Taste the Difference product, which rose by 13% over the festive period.
However, the supermarket has been hobbled by falling sales of electronics, clothing and other general merchandise, sending its stock price down more than 5% on Wednesday.
Despite raising its forecast, Tesco shares fell almost 1% on Thursday.