Mourinho recalled a 2-1 defeat he suffered to the Foxes on Dec. 14, 2015, which turned out to be his last match in charge of the Blues.
When questioned by a reporter about his cropped haircut, the Portuguese played along with the lighthearted mood, per Jake Polden of the Mirror.
The reporter asked Mourinho: "We've been here before as well, you've had your hair cut and your team has become more ruthless, it's not a coincidence, is it?"
In response, the United manager said: "And the last time I sat in this chair, the next day, I was sacked!"
Goals from Henrikh Mkhitaryan, Zlatan Ibrahimovic and Juan Mata gave United victory at the King Power Stadium, and the result took their unbeaten league run to 15 matches and closed the gap on fifth-placed Liverpool to one point.
Per Sky Sports, Mourinho said he believed he was now getting overdue recognition for his playing style in England:
My team is playing very well but for many, many years in my career, especially in this country, when my teams were ruthless and when they were phenomenal defensively and very good in the counter-attack, I listened week after week... it was not enough, in spite of winning the title three times.
It looks like this season, to be phenomenal defensively and be good at counter attack is art, so it's a big change in England.
United's latest three points will raise hopes among their supporters that they can make a late challenge for the Champions League qualification places.
Mourinho has made United a tougher proposition for opponents to break down this season, and the powers-that-be at the club have been pleased with it, according to James Ducker of the Telegraph.
Indeed, they have lost the same amount of league matches as runaway leaders Chelsea, with three, but it's at the attacking end of the field where they have struggled at times to put opposing teams away.
OptaJoe heralded what could be viewed as a breakthrough for United on their current run:
While they were able to cash in against Leicester, there arguably remains a reliance on Ibrahimovic, who has netted 15 times in his debut season in England. Per the official Premier League website, United's next top scorer is Mata, with five.
Mourinho's men face a busy fixture list over the next few weeks, and after Saturday's match against Watford at Old Trafford, United will not play in the league again until March 4 due to cup commitments.
There will also be the challenge of European competition for Mourinho to navigate when his side return to Europa League action with a two-legged last 32 encounter with AS Saint-Etienne of Ligue 1.
While United have kept themselves in the frame for a decent league finish, the upcoming period looks set to be a crunch point in their campaign. Much may depend on the continued form and fitness of Ibrahimovic if they are to reward Mourinho with any silverware in his first season at the club.