The employee-owned firm said today department store sales increased 6.2 per cent year on year to £56.6m in the week to 28 July.
In the previous two weeks the retailer had posted rises of 11.2 per cent and 17.3 per cent respectively.
However, managing director Andy Street said an 86 per cent week on week uplift in sales of London 2012 merchandise "augurs well for an exciting week ahead."
He said the retailer's first half sales growth of 12.9 per cent was "hugely encouraging".
"We substantially outperformed a slow market. While we have added a number of new shops, growth from the established business has been strong."
Street highlighted a trailblazing performance in the half from the johnlewis.com website, which delivered a 43.5 per cent rise in sales and said the firm went into the second half "with confidence provided by strong momentum."