The host nation needed towin all three rubbers in straight setsto snatch a final spot off the unbeaten Spanish pairing of Maria Jose Martinez Sanchez and Tommy Robredo.
But the Scot responded well, winning the third set 6-2 in just 33 minutes before surviving another tie break towin through in four sets in three hours and 27 minutes.
They last clashed at the Sony Ericsson Championships in Doha in November 2008 when Venus dispatched Serena in three hard-fought sets before going on towin her first end of season title.