The two have never been the best of friends.
Big Sam has recently released his new autobiography, imaginatively named 'Big Sam'. It is being serialised in The Sun newspaper and one section seemed to suggest that Benitez had very little to do with Liverpool's Champions League win back in 2005. He went on to criticise him more, stating:
"He didn't like me and he thought he was superior. Here was a trendy foreign manager with all his smart ideas getting beat by some oik from the Midlands.
"I put his comments on the wall of the changing room [at Bolton] but Ivan Campo and Jay-Jay Okocha said, 'We don't need those, gaffer, we'll beat him anyway.'
"Benitez wouldn't talk to me at all and that just made it all the better when we won. I can't stand people who disrespect me the way he did."
Now Benitez has had his say on the matter and is clearly not pleased with Allardyce.
He told Spanish radio this morning, as quoted by the Daily Mail:
"Do you know who Sam Allardyce is? Do you know how many trophies he has won? Well that’s my answer.
"It is what happens when someone has a book to sell. His opinion does not have a lot of value."
The two, who clashed on occasions during their working relationship in the Premier League however they appeared to have buried the hatchet.
But autobiographies always stir up some residual feelings and it is clear to see that there is no love lost between the pair.
Unfortunately it is currently hard to see how Sunderland and Real Madrid will ever meet for a manager grudge match.
But one must always hope.