The fourth-seeded Spaniard kept up her positive comeback from a serious knee injury with a 19-21, 21-13, 21-11 win at the Babu Banarasi Das Indoor Stadium.

It sets up a last-eight clash with Russia's Evgeniya Kosetskaya, who defeated China's Zhang Yi Man 21-17, 22-20 on day three of the Badminton World Federation World Tour Super 300 event.

Marín is the only seeded player through to the quarter-finals following fifth-ranked An Se Young's 13-21, 11-21 loss at the hands of fellow South Korean Kim Ga Eun.

Next up for Kim is compatriot Kim Hyo Min after she overcame home player Ashmita Chaliha 21-12, 21-16.

In the men's singles, India's Srikanth Kidambi secured his spot in the last eight by beating fellow countryman Parupalli Kashyap 18-21, 22-20, 21-16.

Standing between the third seed and a place in the semi-finals is seventh-seeded South Korean Son Wan Ho, a 21-14, 21-17 victor over India's Lakshya Sen.

The most notable casualty today was fourth seed Bhamidipati Sai Praneeth, with the home player losing 11-21, 17-21 to Thailand's Kunlavut Vitidsarn.

Vitidsarn will take on Sourabh Verma, also of India, for a place in the last four after he defeated compatriot Alap Mishra 21-11, 21-18.

There was also a win today for eighth seed Wang Tzu Wei of Chinese Taipei - 14-21, 21-10, 21-14 against India's HS Prannoy - and he will go on to face Malaysia's Soo Teck Zhi, a 21-9, 21-11 victor at the expense of Canada's Bagalur Rajanna Sankeerth, in the quarter-finals.