The ninth seeded Indo-Romanian rallied to shock the three-time champions 5-7 6-4 7-6(9) 7-6(5) in the quarterfinals, in which engrossing tennis was played for two hours and 34 minutes, last night.
Bopanna and Mergea hit 31 winners, 17 of which were aces, and saved three of the five break points they faced in the match.
They next face fourth seeds Jean-Julien Rojer and Horia Tecau, who overcame seventh seeds Marcin Matkowski and Nenad Zimonjic 6-4 6-3 7-6(2) in the other quarterfinal.
The second seeds defeated Croatian pair of Marin Draganja and Ana Konjuh 6-3 7-6(5) 6-3 in the third round.
India's singles challenge ended in the junior singles championships with the defeat of 15th seed Pranjala Yadlapalli. She lost 2-6 3-6 to American Michaela Gordon in the girls singles second round.
There was something to cheer though in the boys doubles as Sumit Nagal and his Vietnamese partner Nam Hoang Ly advanced to the second round with 6-4 7-5 win over Alex De Minaur of Australia and Yosuke Watanuki of Japan.