#3 Chelsea 4-0 Manchester United (Premier League, 2016)
Jose Mourinho was signed by Manchester United right after he was sacked by Chelsea following his second spell with them. That came as a shock to the London club's fans. However, they did not have to wait long to voice their frustration with the person who won them their first Premier League title.
Both United and Chelsea endured bumpy starts to their league campaigns that season. So both teams needed a win when the Red Devils visited Stamford Bridge in October 2016. However, it was Chelsea who had the last laugh as Jose Mourinho's side endured a hiding.
The Blues opened the floodgates after just 30 seconds as they scored four unanswered goals past Manchester United. It was Mourinho's heaviest Premier League defeat at the time.
In a far from memorable return to Stamford Bridge for Mourinho, the Chelsea fans chanted 'you're not special anymore', adding insult to injury.
#2 Barcelona 5-0 Real Madrid (La Liga, 2011)
While a defeat in El Clasico is bitter, imagine being humiliated! That is exactly what happened when Jose Mourinho's Real Madrid went head-to-head against a formidable Barcelona team.
Jose Mourinho had only recently taken charge of Real Madrid following his treble-win with Inter Milan in 2009-10. Madrid were undefeated in La Liga before clashing with Barcelona. What was expected to be a thrilling fixture against two great teams managed by two fine managers turned out to be a damp squib - a lopsided affair.
In Mourinho's first El Clasico game in charge, the Blaugrana scored five goals without reply. Surprisingly, Mourinho kept his job that year and won Madrid's first league title in four years in 2012. He won a few trophies before parting ways with the club in 2013.
#1 FK Bodo/Glimt 6-1 AS Roma (Europa Conference League, 2021)
Jose Mourinho's latest managerial endeavour saw him join AS Roma this summer after a disappointing end to his stint at Tottenham Hotspur last year. He started the 2021-22 campaign on a positive note. His team grabbed a sensational last-minute victory in Mourinho's 1000th managerial game in charge; Roma won that Serie A game 2-1. However, things quickly went south from there.
Eight games later, Mourinho suffered the biggest defeat of his managerial career. A much-changed Roma were routed 6-1 in the inaugural UEFA Europa Conference League by an unheralded FK Bodo/Glimt side.
Glimt had only won the Norwegian league for the first time in their history last season.
However, none expected them to beat a formidable AS Roma side, certainly not in the manner in which they did. Glimt's best-ever previous performance in Europa was a first-round appearance in the UEFA Cup, which they've done three times.
A defeat was never on the books for Mourinho's team. However, Glimt scored three in the first half to turn the game on its head. Any hope of a Roma comeback was thwarted by Glimt, who scored three more in the second half. Carles Perez's first-half strike for Roma was only a consolation on the night.