Lauren Smith and Marcus Ellis defeated Kim Won Ho and Kim Hye Rin 21-11 21-12 to sail through in straight sets at the Ecogreen Syed Modi International Championships in Lucknow.
They will play Mark Lamsfuss and Isabel Herttrich, the German fifth seeds in the next round.
Ellis and Smith are 3-2 up in the two pairs' head to head record.
This was particularly impressive from Smith in her second last eight tie of the day.
Also an added bonus that it took just 36 minutes for the English number one pair to defeat the South Koreans.
Earlier Chloe Birch and Smith were eliminated by Chang Ye Na and Kim Hye Rin of South Korea in their quarter-final. 21-14 22-20 to the fourth seeds.
Reflecting on a busy day Lauren Smith said: "Really happy with the Mixed Doubles win, was good to get revenge after the Women's Doubles loss.
"We kept good discipline in today's mixed and we are hoping to keep the momentum going tomorrow."