The Blues moved quickly to replace the Italian, with former Inter Milan, Liverpool and Valencia manager Benitez agreeing to take charge of the London outfit and end his two-year period out of football coaching.
A statement on the club’s website said: “The owner and the board believe that in Benitez we have a manager with significant experience at the highest level of football, who can come in and immediately help deliver our objectives.
“The 52-year-old Spaniard is due to meet the players at the training ground in Cobham tomorrow.”
Benitez’s arrival comes in the wake of Chelsea’s 3-0 defeat by Juventus in the UEFA Champions League, which has left the holders in serious danger of being eliminated at the group stage.
A win in their final Group E encounter against FC Nordsjaelland, as well as a Shakhtar Donetsk triumph against Juventus, is required for the Blues to maintain their hopes of winning the tournament for a second consecutive season.
After an impressive opening to their Premier League campaign, a run of four games without a win has left Chelsea in third place, trailing Manchester City and Manchester United.
That position, coupled with their struggles in the Champions League, brought an end to Di Matteo’s time at the helm despite delivering continental glory and the FA Cup at the end of last season.
Earlier this year, Benitez had explained to FIFA.com exactly what he was looking for from his next permanent position, after a short-lived and disappointing spell with Serie A side Inter.
“When I talk about a project it has to be a club that can match my desire to fight for trophies,” he said in April.
In the short term, Benitez will have the opportunity to lead a team at the FIFA Club World Cup for a third time, having finished runners-up with Liverpool in 2005 and lifted the trophy with Inter in 2010.