Jol's heavily rotated side were defeated 4-3 at the King Power Stadium after suffering a 2-0 Premier League defeat at the hands of Southampton on Saturday.
And the Fulham manager revealed he felt his side had done enough to progress to the next stage of the competition but for some defensive errors.
"We showed even with nine different players we were the better team in the second half and we should go to the next round but we didn't," Jol said.
"I trust them and I need to trust them and I want to trust them so that was not the problem because I really thought we had a good team out.
"I thought in midfield we had a couple of good players and I had a good bench - I thought Darren Bent could make a difference and Bryan Ruiz showed that he can make a difference so the scenario was okay.
"Giorgos (Karagounis) is a hero for me - he came in and worked his socks off and scored the third goal," Jol added.
"Of course we've got other players who will come in again who were rested or injured. We had four or five who were injured and we couldn't play them so we had to change the team.
"A few boys showed they can play and they can play on Saturday. I thought the spirit was good but we gave cheap goals away."