Manchester United suffered a 4-0 defeat to Chelsea on Jose Mourinho's return to his Stamford Bridge on Sunday.
Here Press Association Sport looks at the Portuguese heaviest losses during his 16-year career in management to date.
Barcelona 5 Real Madrid 0 - November 29, 2010 (LaLiga)
Pep Guardiola's Barcelona dictated possession and the scoreline reflected their dominance, with Xavi and Pedro earning the hosts a half-time lead. A brace from David Villa and a late fifth by substitute Jeffren Suarez condemned Mourinho to his first loss as Real boss. It was a fiery contest at the Nou Camp, with 14 yellow cards issued and Sergio Ramos being dismissed.
What Mourinho said: "This is the first time I have ever been beaten 5-0. It is a historically bad result for us. It is not a humiliation but I am very disappointed."
Chelsea 4 Manchester United 0 - October 23, 2016 (Premier League)
The build-up was focused on the 53-year-old's return to Stamford Bridge for the first time since his sacking in the previous campaign. But it was a nightmare start for Manchester United as Pedro opened the scoring for Chelsea after just 30 seconds before goals from Gary Cahill, Eden Hazard and N'Golo Kante ensured a miserable day for their former manager.
What Mourinho said: "After a defeat 4-0 if I'm going to speak about a referee, you (the media) are going to jump. If we could delete the defensive mistakes, the globality (of the performance) was good."
Borussia Dortmund 4 Real Madrid 1 April 24, 2013 (Champions League semi-final, first leg)
Robert Lewandowski produced a masterclass as his four goals put Real Madrid to the sword. The Poland international netted his first early in the first half with Cristiano Ronaldo equalising just before the break to give the visitors hope. But Lewandowski completed his hat-trick at the start of the second half before converting a spot-kick for his fourth to seal a comprehensive win.
What Mourinho said: "How it went from 1-1 to 4-1, I really don't know. Everything happened in a short amount of time. They were the better team by far - they won every individual battle on the pitch."
:: Mourinho has also suffered five 3-0 defeats during his career. The first came two months into his first job at Benfica, losing 3-0 to Maritimo, and he also lost by the same scoreline to Belenenses two months into what turned out to be a hugely successful spell at Porto.
He suffered two 3-0 defeats in the space of five matches in his second spell at Chelsea, firstly against West Brom in the penultimate match of the 2014-15 season before also losing to Manchester City in the third match of the next campaign.
Mourinho also suffered a 3-0 loss to Sampdoria in the Coppa Italia whilst in charge of Inter Milan in 2009, the season before winning the Serie A, Coppa italia and Champions League treble at the club.