British electricals and mobile phone retailer Dixons Carphone raised its full-year profit forecast after Christmas trading beat expectations.
These had been given an early boost by Black Friday deals in November.
While rivals, such as Argos, have complained that the US-imported Black Friday sales day on November 28 was unhelpful as it pulled Christmas sales forward and then created a lull in spending, Dixons Carphone said the pattern of shopping worked well for it.
Finance Director Humphrey Singer said Black Friday was now its busiest day of the year, surpassing December 26.
"The shape of this key (Christmas) trading period certainly changed but we like big, planned promotional events and were well prepared and able to adapt," he told reporters.
Dixons protects margins by placing particularly large orders with big global manufacturers. In some instances it gets suppliers to devote their factories to one model, bringing down costs. Savings can then be passed on to consumers.
Argos and John Lewis have said retailers may try to rein-in Black Friday promotions this year.
Dixons Carphone, formed by last year's merger between Dixons Retail and Carphone Warehouse, said it expected a 2014-15 pretax profit of £355-375m compared with a previous forecast of £354m.
It said sales at stores open for more than a year were up 7% in the nine weeks to January 3, while gross margins were stable.
Like-for-like sales rose 8% in its main UK & Ireland division, where it trades as Carphone Warehouse, Currys and PC World, ahead of analysts' average forecast for a rise of 5%.
Top sellers included coffee machines, juicers, high speed blenders and ultra high definition televisions.
Sales on the same basis were up 6% in the northern Europe division, compared to expectations of a 3% rise, but fell 4% in southern Europe.
