Mourinho has also been warned he faces further punishment for any more such outbursts.
The Portugese coach was unhappy at the decision not to award a penalty when, with the score at 1-1, forward Radamel Falcao was upended by Saints goalkeeper Maarten Stekelenburg, and criticised referee Robert Madley in post-match media comments.
The FA confirmed last night that the Blues boss had accepted he had breached the regulations.
Following the defeat against the Saints, Mourinho gave a seven-minute flash television interview during which he lamented the calls from officials which went against his side.
“It’s time to be a little bit honest and to say clearly the referees are afraid to give decisions for Chelsea,” he said.
There was better news for champions as goalkeeper Thibaut Courtois revealed he hopes to be back in action from a knee injury by December.
Courtois needed surgery following damage to ligaments in his right knee suffered in training last month.
Courtois revealed the procedure had gone well and he was now set to step up his recovery programme.
“In terms of my knee, it is good. I am doing my rehabilitation and it is progressing fine,” Courtois said.
“I will be (now) starting the bulk of the work with my physio to come back as soon as possible.
“Of course I still have to be careful not to go too quickly, but all being well, I should be back in December.”