Sainsbury's today (9 January) reported that third-quarter like-for-like sales, excluding fuel, came in at 0.9%. While this represents a slow-down from the company's previous 31 consecutive quarters of growth, Sainsbury's was able to increase its market share during the key Christmas trading period. Sainsbury's star-performer was once again its own label offering and the group was upbeat on the success of its promotional strategy. However, when inflation and the contribution from store expansions is stripped out, the group saw sales volumes decline. With the likelihood that the 2013 competitive environment will remain tough, the challenge will be for Sainsbury's to maintain its growth momentum. Here is the City's verdict.