Hearts 2 Hibernian 1
Neil Lennon declared he would consider his future after a 2-1 defeat by Hearts cost Hibernian the chance of finishing second in the Ladbrokes Premiership.
The Hibs head coach branded his players "unprofessional" after some struggled with their footing on the slick Tynecastle surface and then lost out to Steven Naismith's headed winner from a Harry Cochrane free-kick.
Hibs are consigned to fourth unless they beat Rangers by six goals at Easter Road on Sunday.
Lennon said: "We'll go into Sunday and just try and win the game and finish with a highest points total but it's not good enough for me. So I will reconsider my position now in the summer.
"I've got things to think about myself, my own personal aims and ambitions. But I can't watch that in a derby. It's not good enough.
"We have a board meeting next week so we'll see. I have been here two years now and we have made great strides but I've got to think about myself sometimes as well and how I feel about the whole thing.
"Maybe I am a bit over-emotional at the minute but fourth isn't good enough."
Florian Kamberi's penalty cancelled out Kyle Lafferty's (inset) opener but Naismith headed home in the 57th minute to leave Lennon raging.
"We threw it away," he said. "Unprofessional, not good enough. We look like we are going to finish fourth, which is unacceptable for me.
"I told the players before the game to make sure they have the right footwear on. The pitch was perfect but it's one of those pitches where it's hard underneath but a dew on top with the moisture and coldness in the air. Five minutes into the game I had three players slip over under no duress. And then they're uncomfortable and not sure-footed. They looked wobbly at times.
"However, the game hinges on a set-play, which is another bugbear of mine, because we gave them plenty of warnings. The first goal should have been dealt with, the second goal, I don't know what (Paul) Hanlon's doing fouling Lafferty. He's going nowhere. Unprofessional, lost the head. And then we can't defend the set-play.
"And then we miss great chances. We didn't have the gumption to make the difference."
Hibs arrived at Tynecastle on a 12-game unbeaten run but Lennon could not stomach losing touch with Aberdeen with one game left.
"We had a great opportunity to go into Sunday with everything to play for," he said. "Credit Hearts, they played the way we knew they would play. But we didn't rise to the challenge enough for my liking.
"If they are not going to listen to me, if I am not getting my message through to them, then maybe somebody else should come in and maybe they will listen to him.
"Because I can't accept players slipping over and then being nervous and anxious because they haven't got the right footwear. It's just amateur stuff."
Lennon had branded Hearts "irrelevant" to Hibs after his side won the previous derby but Hearts boss Craig Levein had a different viewpoint.
"Well, we put them out the Scottish Cup and stopped them being second," he said. "Pretty relevant to me."