The unseeded Indo-Swiss pair scored a hard-fought 7-6(4), 3-6, 10-3 victory over the Canadian-American team in the second round of the US $4,457,065 hard-court tournament.
They saved eight of nine break-points they faced to topple the eighth seeds in 77 minutes.
It was Paes-Wawrinka's second straight victory over Pospisil-Sock. They defeated the pair in the Paris Masters last October.
Paes had teamed with Andy Murray, another top-5 player, in Montreal last week. They lost to Andy’s brother, Jamie Murray and John Peers in the second round.
Image: Leander Paes (left) and Stanislas Wawrinka at the ATP Masters Western and Southern Open, in Cincinnati.
Photograph: Maddie Meyer/Getty Images
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