He later held up three fingers to the Chelsea crowd, signifying the three Premier League titles he won with the Blues.
A dramatic fightback from 2-0 down to beat Newcastle 3-2 before a two-week global break offered Mourinho a stay of execution, but the pressure is still on the Portuguese to close a seven-point gap on Chelsea, Manchester City and Liverpool at the top of the table.
But Mourinho's team were transformed after the interval, and they arguably deserved to come away with the three points.
They are now sitting at the top of the Premier League table with 21 points, just one point more than Manchester City and Liverpool who are second and third on the PL table respectively. "We didn't sleep in the hotel, everyone stayed at his own house, and I think the players when they woke up - because they read on social media - the pre-match was not easy for them". "We are at the top of the league, we are scoring goals at the moment and we are winning games so now after the worldwide break we want to do the same on Saturday against Man United".
"I have spoken to a member of my staff and have dealt with this immediately".
A scuffle then ensued as Mourinho attempted to argue with Ianni, which took a few minutes to settle down and involved over 20 players and staff. Mourinho says a lack of education was to blame, but, accepted the mistake.
Lionel Messi to miss El Clasico with fractured arm
Writhing in pain on the field, Messi was tended to by team trainers before being substituted off for Ousmane Dembele. However, Rakitic restored Barca's three-goal advantage with a superb volley that sailed into the bottom corner.
Two goals from Anthony Martial appeared to have earned Mourinho's side a comeback win after they went 1-0 down in the first half of the Premier League match. "But I also made mistakes in football matches and will make more".
For Mourinho, the frustration has been building with the team's poor start to the season, and he also has to react better.
Asked whether there could be a club punishment for Ianni, the Chelsea manager said: "I don't know at the moment, I want to speak to him after the game".
"I would love to have him at Manchester United", said Mourinho, whose side trail joint-leaders Chelsea by seven points.
Mohamed Salah scored the only goal as the Reds ended a four-match winless run in all competitions. "Even after the equaliser, remembering that moment, we hugged like two old friends".
"I think they're going to be a near miss", he said on Sky Sports. "It happened with me [in 2014-15] and Antonio [Conte, in 2016-17], and this season he is the best player until now and Chelsea is top of the league because he is the kind who can make a huge difference".