Everton boss Roberto Martinez criticised referee Mark Clattenburg after the Toffees were beaten by Stoke in dramatic circumstances at Goodison Park.
The Potters secured a 4-3 victory in stoppage time thanks to Marko Arnautovic's penalty.
Clattenburg, taking a few seconds as he made the call, awarded the spot-kick after Arnautovic went down in the box under a challenge from John Stones.
And Martinez said following the game: "The feeling is extra frustrating today because you cannot understand how such an experienced referee gives that decision right at the end.
"It is such a wrong call. Someone with his experience should understand the game a bit more.
"Clearly John Stones gets a touch of the ball and from that point on you can see there is a doubt from the referee.
"He does not give it straight away, so he wants confirmation, and he waits for the linesman - who is probably about 45 yards away from the incident - to give him his view.
"It is very disappointing at that point for us to lose a draw."
Martinez - whose side had battled back from being 2-1 down at half-time to lead 3-2 with just under 20 minutes to go - admitted Everton's performance could have been better, particularly on the defensive front.
But the main focus of his post-match comments was Clattenburg, who he felt had also been wrong not to give a penalty following Erik Pieters' challenge on Seamus Coleman in the first half.
"It is a game we didn't deserve to lose and it is one where we should have got a lot more," said Martinez.
"Obviously we want to win these sort of games, but if you can't win it we should never have lost because of that terrible decision from the referee right at the end.
"The disappointment is that he got that one wrong, but it is extra painful when he wasn't consistent throughout the game."
Martinez said he had spoken to Clattenburg after the match, and added: "I have huge respect for Mark's career - he has always been someone I felt was very honest and a perfectionist in what he wants to do.
"But clearly today he was very much out of sorts and his decisions punished us incredibly.
"To give a penalty in the 90th minute, you have to be certain, and you use your experience on that. When you are not certain, it is very strange to see an experienced referee doing that."
Giving his view of the incident, Stoke manager Mark Hughes said: "I didn't think he was going to give it, but credit to Mark - he took his time and thought it through, and I think he made the right decision.
"People will say maybe it was a soft one. Whether the Everton player got contact on the ball will be debated I'm sure, but he has obviously got a lot more contact on Marko Arnautovic and impeded him, and he wasn't able to get a shot off as a consequence. So you would argue it was a correct call."
The first half of a thrilling encounter saw Stoke's Xherdan Shaqiri net a brace - his first goals for the club he joined over the summer in a record deal - either side of a Romelu Lukaku equaliser.
Shaqiri's opener rounded off a fine team move, while his second was a sublime solo effort sent floating from his boot over the stranded Tim Howard from the edge of the box as he met a Bojan Krkic delivery first time.
And Hughes, whose men were building on the 2-0 Boxing Day win over Manchester United and moved up to eighth in the Barclays Premier League, said: "We're delighted for Shaq.
"In recent weeks his influence on games has been really high.
"The only thing missing before today was goals.
"He was always at some point going to make an impact for us and he is starting to do that to great effect, and the goals will help that process even more.
"I was obviously really delighted with the second finish, which showed great technique, but the first goal arguably is just as satisfying because it was a great team goal with Shaq on the end of a good move."
Lukaku made it 2-2 in the 64th minute and Gerard Deulofeu then put Everton ahead before substitute Joselu's leveller 10 minutes from time and Arnautovic's late winner.