First half goals from Christian Benitez and Barry Ferguson helped Blues to their first victory at Goodison Park since 1957 with a 2-1 success against David Moyes' side and a place in the draw for the last 16 of the competition.
"It was a marvellous first half, we scored two classy goals and Barry Ferguson's will be a rival for goal of the season," the Blues boss said after the game.
"The intricate passing, the driving run, the expert finish, it was a wonderful goal.
"Benitez's goal was good, but Ferguson's was stunning. We stood up to them, particularly in the second half when we were facing an onslaught.
"But the first-half performance was instrumental in us winning the game.
"Everton came back at us, we knew they would, but we held on and we must give credit to the team for their resilience and their spirit.
"The lads threw themselves in the way of everything, blocking and heading everything away. The second half was a test of our character and we came through it.
"The run we are on, for a newly-promoted side, is sensational in modern times.
"For a smaller club in the Premier League it is exceptional. But we are enjoying it and we have the character to keep it going."