Needing to win every set of every rubber against Spain to perform a tennis miracle and reach Saturday's finale, the pressure was immediately on Stosur who had won one and lost one of her singles encounters this week.

But after surviving two break points in the first game of the match, Stosur crumbled in the seventh, with the Spaniard was more than capable of dealing with Stosur's high kicking second serve to secure a break.

Martinez Sanchez served out the set 6-4 – despite a break point for Stosur in the decisive game - to put Spain in the final for the fourth time, and give them a chance for a third Hopman Cup title and their first since 2002.

After starting the week as top seeds Lleyton Hewitt and Stosur needed the perfect performance after suffering a shock 2-1 loss to Romania on the opening day of the $1 million mixed-teams' event.

Fourth-seeded Spain, represented by world No.16 Tommy Robredo and world No.26 Martinez Sanchez, sit on top of group A after romping to 3-0 whitewashes over the US and Romania.

Hewitt will play Robredo in his biggest test of the week so far in the men's singles rubber, with the result academic but the Australian's form important ahead of the Australian Open.