Jose Mourinho has risked upsetting Chelsea fans by claiming that the "passion" of Manchester United's supporters is "unrivalled".
The Portuguese coach spent five years across two spells in charge of the Blues, winning seven major trophies, including three Premier League titles.
Mourinho, who took over at United last summer, had a close relationship with Chelsea fans, but it appears as though the supporters of his new club are more impressive.
In a letter to United season-ticket holders, the 54-year-old spoke of the fans' passion, saying that it eclipses the support of his previous clubs, including Porto, Inter Milan and Real Madrid.
"The crowd at Old Trafford must play its part too. I have to say I've been impressed by your dedication and commitment, as season ticket holders here at United," wrote Mourinho.
"I've managed several clubs and I have never seen such unrivalled passion. The stadium is full every time we play and the support the players receive is special. Everybody connected to this fantastic club wants success and this is the same for myself and for my players."
Mourinho will face his former club Chelsea once again when United travel to Stamford Bridge for an FA Cup quarter-final on March 13.
