Customers surveyed during December said their main reasons for shopping at the new Express in Southborough, Kent, were convenience, freshness, quality, and value, a spokeswoman said.
But she added: "Some customers told us they missed our Value range."
Tesco's marketing department, which conducted the survey, found that the Express was mainly cannibalising sales from the nearest Tesco supermarket in Pembury, rather than from the local high street.
Graham Manning, who owns the nearby Sweet Centre, said the store had less impact on trade than he had expected. He said: "My trade seems normal, though Sundays seem a bit slow."