David Jones shares slipped yesterday after the upmarket store chain confirmed a downturn in second-quarter sales and warned this half would be "extremely challenging". The group reported an 11.8 per cent rise in second-half sales to $743.6m, excluding GST and wholesale sales tax, a better performance than that of its struggling rival, Coles Myer's Myer Grace Bros. That group last week revealed a six per cent decline in first-half sales after a particularly poor January.