Pre-tax profit leapt a massive 123% to £194m in the six months to 7 October, on sales up 8.3% at £9.549bn. Like-for-like sales during the period increased 6.2% excluding petrol.
However, analysts were disappointed that profit and margin growth had not been stronger.
There were also concerns that Sainsbury's operating margin of 2.43% trailed Morrisons and Tesco.
“The company may be pleased with this result but Morrisons' margin is now at 2.7% having started from a lower level,” said David McCarthy, a retail analyst with Citigroup.
“We question the ability to deliver some of the more optimistic estimates of increases in operating margins and ensuing profit forecasts,” added Seymour Pierce analyst Richard Ratner.