BBC coverage of Wales v England on Tuesday evening was watched by a peak audience of 18.7 million.
The figure, which combines BARB overnight data with non-TV streaming data across all devices, is the biggest UK audience of the World Cup so far.
The BBC iPlayer has been a particular beneficiary of the tournament. Last week saw the full range of BBC programmes on iPlayer streamed a record 165 million. An increase of 20% week-on-week and
breaking the previous high by 12m streams.
The BBC has created a pop-up channel on iPlayer called World Cup Extra, based around its World Cup matches, which are shared with ITV.