Britain's third-largest supermarket group said sales at stores open over a year, excluding fuel, rose 1.4% in the 12 weeks to June 9.
Sainsbury's overall UK sales rose 3.6% in the period, and improvements to its website allowing shoppers to order from mobile phones helped drive a 20% rise in online sales.
The firm, which lags Asda (NYSE: WMT - news) and industry leader Tesco (LSE: TSCO.L - news) by market share, said it outperformed the market and it was well placed to continue to do so, despite expecting the market to remain competitive.
"Customers continued the habit of savvy shopping to save money in order to be able to treat themselves on special occasions, shown by strong sales in the lead up to the Jubilee celebrations," chief executive Justin King said.
Although the result fell within a Reuters analyst forecast of growth of 1% to 2.25%, it represents a slowdown from 2.6% in the fourth quarter of the 2011-12 year.
Shares opened slightly lower on Wednesday morning as the like-for-like sales figure came in slightly below some City forecasts for growth of up to 2%.
Sainsbury's performance looks good relative to Tesco, which on Monday posted a 1.5% fall in first quarter underlying sales.
It was the third quarterly fall for Tesco, Britain's largest grocer, which accounts for around £1 in £10 spent in British shops.
However, Tesco's first quarter reporting period did not include the recent Jubilee holiday.
Mr King added: "Just as in 2011, the quarter was characterised by five bank holidays, a royal event and periods of unseasonal weather."
:: Supermarkets and other retailers have seen a huge increase in 'winter warmer' sales such as soups, as summer continues to be drowned out by heavy rain and colder weather.