West Ham manager Sam Allardyce was "baffled" by the decision which handed Everton their opening goal in the 2-1 win at Goodison Park.
Even a post-match explanation from referee Mark Clattenburg as to why Romelu Lukaku's strike was allowed to stand despite him being offside immediately before Ross Barkley's shot rebounded to him failed to appease the Hammers boss and he will be taking up the matter with officials' chief Mike Riley next week.
"A little bit of it was our fault but that decision baffled me so we have to be frustrated," said Allardyce.
"The first shot was blocked by Winston Reid and it falls to Lukaku who is two yards offside.
"For me there will be some way forward next week for an explanation.
"I have had an explanation from the referee but I won't discuss that publicly, I'll discuss it privately with the PGMOL (Professional Game Match Officials Limited) next week."
After a couple of meaty challenges from James McCarthy - who provoked an all-out melee after going over the top on Morgan Amalfitano - and Steven Naismith Allardyce, whose sides down the years have been accused of being over-physical, claimed they asked Clattenburg for greater protection.
"I think they were yellow cards. Naismith's challenge on Mark Noble was probably the worst of all and because there wasn't a furore it went unnoticed," he added.
"Noble ended up coming up off injured because of that.
"They showed a certain degree of physicality and we had to ask the referee to protect us and I don't think he did that too well.
"It is a part of the game we accept but the most frustrating thing is our controllables.
"We have been very good this year at converting chances with very good delivery in the final third but our finishing was not good enough and because of that we have ended up losing and a referee's decision has contributed to it."
Allardyce was also unhappy about the concession of the winner, which came from a quick counter-attack and saw Clattenburg make the right choice in playing advantage to allow Leon Osman to score on his 400th appearance after Mauro Zarate had equalised four minutes after coming off the bench.
"One punt up the middle was a hugely disappointing way to concede," said the West Ham boss.
"There are opportunities when Everton try to get Lukaku in to get running at players but to allow him to get in from a clearance, defensively that was the only disappointing thing today and unfortunately it has cost us a goal."
Everton manager Roberto Martinez was delighted with the way his team bounced back to secure victory.
"That is the most satisfying win we have had this season, although you will see games that are more glamorous," he said.
"You know you have been in a game, it is one of those wins you get through character, personality, winning mentality and that gives me a real satisfaction."
On the contribution of Osman, who added his name to an elite dozen who have passed the 400 landmark, the Toffees boss said: "I thought he was outstanding throughout the game.
"He was marshalling the back four and dictating the play so the last player you expect on a counter-attack was Leon Osman.
"It is a reflection of what he is as a footballer and it was a fitting goal.
"He is a great ambassador for our football club."