The sixth seeded pair of Rohan Bopanna and his Romanian partner Florin Mergea booked a quarterfinal berth in US Open on Monday.Bopanna and Mergea took 2 hours and six minutes to beat 9th seeds Daniel Nestor and Edouard Roger-Vasselin 6-7, 6-4, 6-3. The Indo-Romanian pair was tested in the first set by its opponents as they conceded the tie-breaker.The duo came from behind and gave no chances to Nestor and Vasselin in the next two sets. Bopanna and Mergea will face Dominic Inglot and Robert Lindstedt in the quarterfinals.Bopanna-Paes clash? The mixed doubles duo of Leander Paes and Martina Hingis are set to take on the Romanian duo of Simona Halep and Horia Tecau in the quarterfinals. Paes will face Bopanna in the mixed doubles semis, if both Indians win their respective quarterfinal matches.Victoria Azarenka reached the US Open quarterfinals for the fourth straight year. The two-time Australian Open champion beat 46th-ranked American Varvara Lepchenko 6-3, 6-4 on Monday.Also read: Federer faces danger match against big-serving Isner In the meanwhile Azarenka introduced a new fashion statement to Arthur Ashe Stadium: gauze wrapped around both biceps. She joked in an on-court interview that after throwing around a football Sunday – she does it for fun and to help with her service motion – she wanted to look tough like an NFL player.Danger match for Federer Swiss second seed Roger Federer faces a danger match against big-hitting American John Isner in fourth-round action at the US Open on Tuesday morning. The five-time US Open Champion will start as favourite, but will take nothing for granted when he takes on the 13th seed for the final match of the night.advertisementWawrinka battles hard Meanwhile, fifth seeded Stan Wawrinka won the first set against USA’s Donald Young 6-4. But the unseeded Young came back strong and won the second set 6-1. But, Wawrinka made light work of the American in the third set. Third seeded Briton Andy Murray and 15th seeded South African Kevin Anderson will be seen fighting for a quarterfinal spot at the Louis Armstrong Stadium.