David Nugent's penalty put the Foxes ahead, before Jo Kuffour levelled matters for the hosts midway through the first half, with Sean St Ledger grabbing the winner with 95 minutes on the clock.
Pearson said: "Competitions are always going to throw up difficult games and we were expected to win this.
"They had nothing to lose and I thought it was a good game of football.
"Both sides wanted to win it and we got that late goal, we had plenty of chances and they have scored a strike that is of exceptional quality.
"These games are never easy to negotiate and I'm glad to get through it in 90 minutes. Sometimes it does not go your way but it went our way tonight.
"I thought our delivery from set-pieces was very good and we were able to sustain the pressure towards the end and get the goal that we needed."
Wycombe boss Gareth Ainsworth admitted: "It was a cruel blow but I feel like a winner tonight.
"The way we performed, approached the game and stood up to a Premiership-contending team was outstanding.
"Every supporter who sang their hearts out should go home proud because I certainly am.
"I can see a good future from these last two performances, I want to bring the good times back to Wycombe Wanderers.
"They are tired more than deflated."