Leicester were made to battle hard by Blackpool before booking their place in the third round of the Carling Cup.
Mark de Vries got Leicester's first after 17 minutes, but the hosts failed to add to their tally despite a strong first-half display.
Their League One opponents stepped up a gear after the break and got back into the game through Keigan Parker's strike in the 68th minute.
But De Vries pounced to hit the Foxes' winner 11 minutes from time.
Leicester: Henderson, Stearman, Johansson, McCarthy, Sheehan, Sylla (Chambers 90), Gudjonsson, Kisnorbo, Hamill (Wilcox 57), Hammond (Hughes 75), de Vries.
Subs Not Used: Logan, Maybury.
Goals: De Vries 17, 79.
Blackpool: Pogliacomi, McGregor, Butler, Clarke, Burns, Wiles, Grayson (Anderson 86), Doolan, Donnelly, Prendergast (Blinkhorn 30), Vernon (Parker 46).
Subs Not Used: Jones, Paterson.
Booked: McGregor, Clarke.
Goals: Parker 68.
Ref: C Penton (Sussex).