Mikel lifts lid on Ancelotti anger
"The manager was really, really mad with the way we played in the second half," the player told the club's website on Wednesday.
Chelsea, who had already qualified for the last 16, drew 2-2 after a glaring error from Mikel allowed the Cypriot side to equalise in the 87th minute.
"It was the worst display since I came here," Ancelotti said after the game.
"In the second half we lost intensity, lost concentration, we played too slowly and too soft."
The Premier League leaders are without a win in their last three games after they lost to Manchester City and exited the League Cup to Blackburn.