The 20-year-old midfielder, who signed a new long-term contract with the Reds in January, played 84 minutes as Jon Dahl Tomassons side knocked out Premier League opposition to reach the last eight.
Having been in and out of the side since the turn of the year, this was Mortons first start for Blackburn since their league draw at West Brom in mid-February.
And he came through with flying colours, with WhoScored giving him a 7.5 rating for his performance, the second best out of any of Blackburns players.
Morton started in a double pivot, alongside Lewis Travis in Blackburns 4-2-3-1 formation, and was up against a Leicester side which was almost at full strength.
Goals from Tyrhys Dolan and Sammie Szmodics gave Blackburn a 2-0 lead at the King Power Stadium, with Kelechi Iheanacho scoring a consolation for the hosts.
The draw for the quarter-finals will take place on Wednesday evening, and theres every chance Morton will face a top-flight side once again.
