Kenyon knows Grant is not a popular choice among the fans.
But he said: "Avram will be more popular if he wins on Sunday and if we are more successful over the next five years than in the last three it will be the right decision."
Kenyon told Mourinho earlier in the week that he had to deliver two European Cups over the next six years. Can Grant do the same?
"I don't think appointing Avram is a risk. If I look where we were three and a half years ago, the structure is infinitely better, the squad is unrecognisably better and we are evolving. The club has changed, we are on a different level to where we were three years ago.
"We are 100 per cent supportive of Avram. There is a risk with everything but we are comfortable that this appointment has been made in the best interests of the club going forward.
"I was party to this decision. If I didn't support it I wouldn't be here. I'm not embarrassed."
The suspicion is Grant will do Abramovich's bidding because he is a friend of the owner and will be grateful for the job.
Chairman Bruce Buck refuted the allegation and insisted Grant was in this for the long haul. Buck said: "We firmly believe that Avram can build on Jose Mourinho's remarkable success.
"He was not appointed because he was Roman's friend. He doesn't make important appointments on a whim. It was made on the basis of merit. This is not a backward step, it is a step forward.
"We don't argue that Jose's record on paper is more successful than Avram's. However, it is important that there is mutual confidence between the manager, the board and the owner.
"We believe our ambition is in accord with Avram's."