Leicester will feel aggrieved Derby County goalkeeper Jonathan Mitchell got away with a clear handball outside of his area during Wednesday's FA Cup replay.
However, Martin O'Neill believes it was impossible for referee Mike Jones and his linesman to have seen the incident.
Mitchell came flying out of his box to deny Leicester forward Ahmed Musa and should have been sent off after replays showed the ball clearly struck the 22-year-old goalkeeper's arm. However, Musa was instead booked for his protests.
Leicester did go onto win the game 3-1 in extra-time to face Millwall in the fifth round and former Foxes boss O'Neill feels the referee's view was blocked.