Fla thumped Chelsea 3-1, with Jackson seeing red just six minutes after coming on in the second-half. The Senegal international was sent off for a nasty challenge on Lucas.
Chelsea boss Enzo Maresca had little to say about post-match: “It was a red card, so nothing else to say. They deserved to win.”
Meanwhile, Obi Mikel, speaking on DAZN, declared: "Unbelievable. Stupid, stupid, stupid mistake.
"I don’t know what was going through his head. Your team needs you and he does that!
"He did that at Newcastle in an important game. He got a red card. And now he's done this again. You can't keep making mistakes like this."
Jackson had started the tie on the bench as Maresca went with Liam Delap in attack and Obi Mikel continued: "I don’t care what his frustration is (Delap starting). This is a massive football club and it's about competition.
"If you’re angry or p****d off, then you have to embrace it. We need competition."
He added, "Jackson needs to have a word with himself, where do you want to go with your Chelsea career?"