The England Vs. USA World Cup match had 19m viewers in the UK and 17m in the USA

"TV1's coverage of England's 1-1 World Cup draw with the USA peaked with nearly 20 million viewers on Saturday, 12 June.
ITV1 HD's coverage of the match suffered an embarrassing fault after it cut to an ad break just as Steven Gerrard scored England's goal. There was no interruption to ITV1.
World Cup Live averaged 13.160 million viewers and a 56% share of the audience, between 6.15pm and 9.45pm, according to unofficial overnight figures.
The game itself, which kicked off at 7.30pm, averaged 17.65 million, with a 15-minute peak of 19.415 million – a 69.8% share – between 9pm and 9.15pm."
Source: BARB data, reported by The Guardian, 14th June 2010

"Viewership for the 2010 FIFA World Cup is up significantly on ESPN/ABC and Univision.
Through Sunday, the World Cup is averaging a 2.6 U.S. rating and 4.2 million viewers on ESPN and ABC, up 63% in ratings and 80% in viewership from the comparable point in 2006 (1.6, 2.3 mil).
ABC drew a 2.8 rating and 4.7 million viewers for Sunday's Germany/Australia match, according to Nielsen fast-nationals, up 27% in ratings and 40% in viewership from Mexico/Iran on the first Sunday of the 2006 World Cup (2.2, 3.3 mil).
Also on Sunday, ESPN drew a 2.0 and 3.0 million for Serbia/Ghana.
Not surprisingly, Saturday's USA/England match on ABC stands as the top telecast of the World Cup, with a 7.3 and 13.0 million viewers.
Over on Univision, the World Cup averaged 3.2 million viewers for the first two days, up 49% from 2006.
Saturday's USA/England match drew 4.1 million viewers on Univision, the second-largest audience ever for a USA match on the network. USA/England is not the network's top telecast of this year's World Cup, however; the Mexico/South Africa opener drew 5.4 million viewers."
Source: SportsMediaWatch, 14th June 2010