West Ham United manager Sam Allardyce accused Chelsea defender Branislav Ivanovic of diving in his side's 2-0 loss at Stamford Bridge.
Chelsea were comfortable winners on Boxing Day, but it might have been more straightforward had they added to John Terry's opener before the interval.
Hammers goalkeeper Adrian saved well from Gary Cahill and Ivanovic went down in the box, angering Andy Carroll and West Ham.
Hammers boss Allardyce said: "I thought he went down looking for a penalty.
"They try and make the referees' mind up for them. We all know that staying on your feet does not get rewarded if you're fouled. We all know that."
Allardyce was reluctant to comment further, adding: "I'm not paying any more money to the FA."
Chelsea manager Jose Mourinho, however, felt Ivanovic deserved a spot kick. "I think it's a penalty," the Blues boss said.
"On television it looks a penalty, for me. I think the other guy grabs him. But no reaction until Carroll reacts negatively."
It was "just an isolated situation", according to Mourinho. "The game was good, aggressive, but correct," the Chelsea manager added.
"The only guy that dived was [Enner] Valencia. It was not in the box, it was outside the box. Nobody reacted negatively to that."
West Ham face another test of their European ambitions at home to Arsenal after disappointing Allardyce with their first-half showing.
"I'm angry with the first half, the way we approached the game," said Allardyce.
"We didn't play like I asked the players to play. They got too sucked into a negative style, passing it sideways and backwards instead of forwards into the right areas.
"As good as Chelsea were, and as talented as they are, our goalkeeper was in great form but the two goals were so avoidable.
"We got better at the start of the second half and then gave a stupid goal away. We created our best chances towards the end of the game. That was too late, and we didn't take any of them.
"I have no complaints about the result."
Information from the Press Association was used in this report.