Veteran Indian tennis player teamed up with Belgium's Sander Gille to enter the quarterfinals of the ATP 250 Boss Open on Wednesday but N Sriram Balaj and Yuki Bhambri went down fighting with their respective partners.
Third seeds, Bopanna and Gille quelled the challenge of local combination of Jakob Schnaitter and Mark Wallner 6-3, 5-7, 11-9 in one hour and 21 minutes.
They are now up against American Taylor Fritz and Czech Republic's Jiri Lehecka.
India's number one doubles player Yuki Bhambri and his American partner Robert Galloway fought their hearts out before losing their opener.
In a match where both sets were decided by tie-breakers, the Indo-American combination lost 6-7(5), 6-7(5) to Santiago Gonzalez from Mexico and Austin Krajicek from the USA in one hour and 34 minutes.
Balaji and and his Mexican partner Miguel Reyes-Varela fought tooth and nail before losing 7-6(5), 3-6, 5-10 to the second-seeded French pair of Sadio Doumbia and Fabien Reboul.