Great Britain's Jamie Murray and Johanna Konta have been eliminated in the first round of the mixed doubles.
The pair initially got the nod over Andy Murray and Heather Watson but while their teammates got through to the last eight after entering the draw as alternates, Murray and Konta lost out to USA's Jack Sock and Bethanie Mattek-Sands.
Aside from Sock's huge serve, there was little between the two sides but that factor proved pivotal as Murray and Konta created just one break-point opportunity all match.
That resulted in one break of serve being enough for USA in each set as they eased to a 6-4 6-3 victory.
