While Devvarman tamed American Jesse Witten 7-5, 6-0, World No 263 Myneni upset ninth seeded American Donald Young 6-7(2), 6-3, 6-4.
Meanwhile, the other Indian in the fray, Sanam Singh, lost 0-6, 5-7 against Australian 12th seed Samuel Groth.
Myneni now takes on top seeded Matthew Ebden while Devvarman will face Christian Harrison.
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