Blackburn, led by former Malmö FF coach Jon Dahl Tomasson, paved the way for a bang when Tyrhys Dolan capitalized on a defensive blunder in the first half.
When Sammie Szmodics then made it 2-0 after the break, the surprise of the evening was clearly in the works. Kelechi Iheanacho reduced but Blackburn managed to hold on for victory.
It was by a small margin. In added time, Daniel Amartey headed in the post as Leicester chased an equaliser.
Fulham can also look forward to a quarter-final after 2-0 against Premier League fellow Leeds at home to Craven Cottage.
João Palhinha sent in the first goal of the match close to one post after 21 minutes played. In the third and last extra minute of the first half, Leeds had a header on the post.
Manor Solomon decided when he screwed in 2-0 quarter into the second half.
Bristol City faced the task of beating Manchester City. Not unexpectedly, it was too difficult.
After just seven minutes, Phil Foden broke the deadlock at Ashton Gate and with a quarter of an hour left, the English national team player made it 2-0. Kevin De Bruyne completed the scoring with his 3–0 goal.
Brighton booked their place in the cup quarter-finals thanks to Evan Ferguson’s goal in the away game against Stoke.