Newcastle sacked Steve McClaren in March and replaced him with Benitez who, after three defeats in a winless first four matches, has since managed to stabilise the club to a degree.
However, it appears it could be too little too late as their fate is out of their own hands after Saturday’s goalless draw at already-relegated Aston Villa.
The point extended their unbeaten run to five matches under Benitez but they finished the day in the bottom three after north-east rivals Sunderland twice came from behind to beat Chelsea 3-2 at the Stadium of Light.
Sunderland could now send the Magpies down with victory at home to Everton on Wednesday night.
“I don’t think it is fair to say what might have happened if I had come at a different time,” said Benitez. “We have to wait and see and we just have to be ready for the weekend, that is it. We still have to play one more game, and we want to get three points.”
Newcastle created the better chances at Villa Park but were wasteful in front of goal, most notably in the second-half through Jack Colback and Aleksandar Mitrovic — who also went very close to breaking the deadlock with a header.
Benitez said: “We tried to do what we had to do. We changed some players and put some offensive players on the pitch, but it was not enough.
“But we couldn’t change too much because they played with five at the back and we had to be really precise when we passed and crossed the ball.”
Before Newcastle play again their future could be decided by bitter rivals Sunderland.
Asked if he would be watching the Black Cats’ game in midweek, Benitez said: “Maybe, but what we do doesn’t change too much.
“The main thing is that if they don’t get the result, then afterwards we have to be ready.”
A rare positive for Villa from this dismal season could be the emergence of teenage defender Kevin Toner.
The Republic of Ireland U19 international made his second successive start against Newcastle on Saturday and kept in-form winger Andros Townsend quiet as he helped Villa to only a fourth home clean sheet of the campaign.
Caretaker boss Eric Black has been impressed with how the youngster has made the transition into the first team with such ease.
He said: “I thought he was outstanding. Andros Townsend has been their best player in the last four or five games, he’s been outstanding and we knew that.
“We looked at the video and the biggest threat was down the right-hand side which was a big ask for Kevin Toner but, my goodness, did he stand up to it.
“He deserves enormous credit for coming into a difficult situation with his head held high and not only that, he has performed at a Premier League level.”
Bunn, Bacuna, Lescott, Clark, Hutton, Westwood, Sanchez, Gana, Toner, Ayew, Sinclair (Hepburn-Murphy 90)
Guzan, Richards, Traore, Gil, Lyden, Grealish
Darlow, Anita, Mbemba, Lascelles, Dummett, Tiote (Perez 68), Colback (De Jong 90), Townsend, Sissoko, Wijnaldum, Cisse (Mitrovic 52).