Tesco's sales continued to decline over the past three months, according to figures from market researcher Kantar Worldpanel, although at a slower rate than before.
The statistics from the industry analyser show Tesco's market share dropped to 28.8%, down from 30.1%, in the 12 weeks leading to 12 October.
Sales were down by 3.6% in the same period, although this is at a slower pace than the 4.5% decrease the beleaguered supermarket experienced in September.
Tesco shares rose 2.2% in value in early morning trading on the back of the news.
Waitrose had a great quarter with its market share reaching 5.2% - a record high for the premium grocer.
Budget stores Aldi and Lidl continued to snap up market share as they gained 27.3% and 18.1% respectively to finish with a final score of 4.8% for Aldi and 3.5% for Lidl.
Asda was the only "top four" supermarket to increase its market share as it rose by 1% to 17.3%. Morrisons' claim of the total spend fell to 11% whereas Sainsbury's dropped to 16.1%.
Fraser McKevitt, head of retail and consumer insight at Kantar, said: "We are seeing clear polarisation of the market with both the premium and discount ends of the market gaining share, while the mainstream grocers continue to be squeezed in the middle.
"Asda has again emerged as the winner among the big four, growing sales ahead of the market, up 1% over the past year, boosting its share to 17.3%. Tesco is yet to see substantial improvement, however it seems it may be turning a corner as sales are down 3.6%, which is the grocer's best figure posted since June."