The Blues' Premier League title bid suffered considerable damage as Fabio Borini struck an 82nd-minute penalty to end Mourinho's 77-game unbeaten record at Stamford Bridge.
The decision to award the penalty was shrouded in controversy as Dean pointed to the spot after striker Jozy Altidore went down under a challenge from Cesar Azpilicueta, and Mourinho wished to congratulate the official on a "fantastic performance".
"Congratulations to my players because they gave what they have and what they don't have," he told Sky Sports News.
"Congratulations to Mike Dean, because he made a fantastic performance. And congratulations to [referees' chief] Mike Riley, because what they did during the season was fantastic for the way the championship is going.
"Congratulations to Sunderland, because they won. Congratulations to all of them - and I have nothing more to say."
League leaders Liverpool can move five points ahead of the West Londoners in the table with three games remaining if they win away Norwich City on Sunday.