Chelsea boss Jose Mourinho criticised his “naive” medical staff for treating Eden Hazard in their draw with Swansea.
The Blues, who had keeper Thibaut Courtois sent off, were down to nine men for a period after staff ran on to treat Hazard following a trip, despite him not appearing to be badly injured.
If a player receives treatment, they must leave the field.
“I was unhappy with my medical staff. They were impulsive and naive,” Mourinho told Sky Sports.
“Whether you are a kit man, doctor or secretary on the bench you have to understand the game.
“You have to know you have one player less and to assist a player you must be sure he has a serious problem. I was sure Eden did not have a serious problem. He had a knock. He was tired.”
Chelsea were already struggling to cope against Swansea’s extra man before Hazard was tripped by Gylfi Sigurdsson with six minutes remaining, leading to Mourinho’s frustration.
It was an eventful match for Premier League champions Chelsea. Courtois suffered an injury scare in the warm-up before he was was dismissed in the 52nd minute after bringing down Swansea striker Bafetimbi Gomis.
Replacement goalkeeper Asmir Begovic came on for his debut after an £8m move from Stoke, with opening goalscorer Oscar making way. Gomis scored the resulting penalty.
“I don’t want to talk about it,” Mourinho said of the referee’s decision.