The US pairing of Isner and Venus Williams were set to face Spain’s Fernando Verdasco and Anabel Medina Garrigues, with the winner to progress to Saturday’s final.
However, Isner withdrew from the tournament citing a right knee problem, handing Spain a 3-0 victory and passage into the final for the sixth time.
Spain will face Serbian top seeds Novak Djokovic and Ana Ivanovic or Australian surprise packets Bernard Tomic and Ashleigh Barty in the final.
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