Interim boss Benitez again confirmed he will depart Stamford Bridge this summer at the end of his short-term contract.
Real Madrid head coach Mourinho, who left after three years as Blues boss in September 2007, has been strongly linked with a return, with a date of July 1 mooted.
"The next year there will be another manager," said Benitez, who replaced Roberto Di Matteo in November.
"I think everybody knows who will be here."
Due to his prior association with Liverpool, where he regularly crossed swords with Mourinho both domestically and in Europe, Benitez was an unpopular appointment among fans, the majority of whom adore the Portuguese.
He would not be drawn into naming names, but it was clear Benitez was responding to the clamour for Mourinho.
The Spaniard said: "I will concentrate on my job now. I have to concentrate on my job. It's not my concern now."
Benitez has quietly moved within sight of his targets since the vitriol towards him quietened down in the wake of his plea to supporters following the FA Cup win at Middlesbrough in February.
Chelsea are in next week's Europa League final against Benfica and well placed in the Barclays Premier League for a return to the Champions League.
Victory in Wednesday night's London derby with Tottenham would see third-placed Chelsea move six points clear of Spurs with two games to play and a far superior goal difference.
Benitez, who has been linked with German side Schalke, would not comment on his own future and preferred to focus on Spurs.
"My future is Tottenham, after we will see," he said.
"At the moment I'm just thinking about Tottenham and what we could do.
"I have to keep doing my job, that is trying to prepare the team properly for every game and the agents, they have to do their jobs."
The victory over Manchester United was Chelsea's fourth in five games.
Captain John Terry was an unused substitute at Old Trafford, but has revealed in an interview with Spanish sports daily Marca that he and midfielder Frank Lampard regularly keep in touch with Mourinho.
Asked about Terry's comments, Benitez said: "My concern is if they [the players] are in contact with me. We talk every day and we talk about what we have to do."
In the opposite dugout at Stamford Bridge on Wednesday night will be another former Chelsea manager - Tottenham's Andre Villas-Boas.
Asked to appraise the Spurs boss, who suggested he was undermined by senior players while at Chelsea, Benitez insisted he has no such problems.
"I think he's a good manager, he's working hard for his new team," Benitez said, before commenting on his squad.
"What I find every day is a very good group of players, keen to learn, ready to do things and to improve.
"You could see a lot of improvement this year. It's a good group of professionals."
Benitez also praised Gareth Bale but insisted Chelsea had no special plans for the PFA Player of the Year and said Spurs should be wary of the likes of Juan Mata and Eden Hazard, who is available after missing the Manchester United win with a calf injury.
The Old Trafford triumph saw the Blues move within sight of second-placed Manchester City and Benitez, who is keen to wrap up Champions League qualification prior to next week's trip to Amsterdam, is looking upwards, rather than behind to Spurs and Arsenal.
"It [qualifying before the final] could be important for us," he said.
"If you have the qualification done, then you can concentrate a little bit more [on the final].
"Still we want to finish in the top three or even more - it depends on the other results.
"We will try to win every [game], but if you have guaranteed a position it's always easier."