Sales at John Lewis department store jumped 7.6% year-on-year to £85.4m in the seven days to September 16.
The retailer said its fashion department had an “exceptionally strong week”, with sales up 18.4% compared with the same period last year.
Both mens and womenswear enjoyed double-digit growth, as shoppers refreshed their autumn and winter wardrobes.
Its own brand womenswear collections performed well too as its new Modern Rarity Eudon Choi collection hit shelves.
Beauty sales were up 10%, supported it said by new launches. John Lewis home sales rose 5.8%, with gifts and cookware jumping 7.6% driven by back-to-uni demand.
At upmarket grocer Waitrose, sales excluding fuel edged up 1.1% to £126.3m last week.
The grocer said trading during the period was aided by its half price event and the launch of the essential Waitrose campaign.
Cooler weather compared to last year’s warmer temperatures led to increased sales of soup – up 25%. And the renewed popularity of Great British Bake Off led to sales of baking ingredients rising by 13%.
Across the partnership, sales rose 3.6% last week to £211.8m.