Chelsea were beaten 3-0 by a Lionel Messi-inspired Barcelona at the Nou Camp.
The game was level at 1-1 heading into the last-16 second-leg clash but Antonio Conte’s side got off to the worst possible start.
Messi opened the scoring in just the third minute, beating Courtois at his near post.
Belgium international Courtois took full responsibility for the goal in his post-match interview.
And Wilkins says Chelsea’s task was made that much harder by the goalkeeper’s error.
“It (the draw) was really important,” Wilkins added.
“You have to go to somewhere like Camp Nou with something to defend.
“And then, within two minutes, you let in one at the near post – that was appalling goalkeeping from Courtois.
“The difference at this level is football is if you have a little genius, you’ve got someone real in your pocket; Messi just comes up with stuff that’s outrageous.”
Ousmane Dembele doubled the hosts’ lead before Messi sealed the victory after half time.
Barcelona will find out their quarter-final opponents in tomorrow’s draw at 11am.