The unseeded Indo-Swiss pair eked out a hard fought 7-6(4) 3-6 10-3 win over Canadian-American team in the second round of the USD 4,457,065 hard court tournament.
It was Paes and Wawrinka's second consecutive win over Pospisil and Sock, whom they had defeated in the Paris Masters last October.
Singles world number 5 former doubles number one Paes held off the eight seeds in one hour and 17 minutes, saving eight of the nine break points they faced.
Paes and Wawrinka will fight it out with either Feliciano Lopez and Max Mirnyi or fourth seeds Simone Bolelli and Fabio Fognini for a place in the semi-finals.
Another Indian in the fray is Rohan Bopanna with Romanian partner Florin Mergea. The fifth seeds had got a bye in the first round and face French pair of Pierre-Hugues Herbert and Nicolas Mahut in the pre-quarterfinals.
