Liverpool boss Benitez has had to listen to Mourinho's suggestion that the Anfield men have been playing "testimonials" for weeks because they have only one trophy to play for.
The Chelsea manager has also been critical of Benitez's decisions to rest players ahead of Liverpool's Champions League clashes.
But now Benitez, ahead of Tuesday's decisive semi-final second leg at Anfield, claims that by trying to do the same in the 2-2 draw against Bolton on Saturday, Mourinho lost Chelsea their Premiership crown.
"It has cost him the league title," Benitez said.
And that, believes Benitez, will make the pressure-cooker atmosphere at Stamford Bridge even more difficult for Mourinho to handle.
Benitez even took a sly dig at Mourinho's 'Special One' tag, saying: "We have our special ones here, they are our fans, who always play with their hearts."
He added of Chelsea: "They know the pressure they have, but everyone has their own problems. We want to win this game, we want to finish third and, as for them, I do not need to put them under more pressure because they know full well what pressure they are under to win things.
"They try to win everything - that is enough pressure without me saying anything.
"They know the pressures they are under, you only have to ask Mr Abramovich what he wants, the Champions League or the Premier League. They know.
"It is clear they will be under pressure because they were talking about trophies, trophies, trophies. Maybe they have one less to win now and that makes the Champions League their priority."
Mourinho has also been critical of Liverpool's fans over the past week, but Benitez hit back by saying that, unlike Chelsea, Liverpool do not need to hand out free flags to get their fans in the right mood.
He added: "At Stamford Bridge, we showed that our supporters won their battle, even though Chelsea had their fans all with flags to wave. But our supporters were there with their hearts.
"We do not need to give away flags for our fans to wave - our supporters are always there with their hearts and that is all we need.
"I aim to be concentrating on one competition after the semi-final, and I do not worry whether Chelsea have one or two to think about.
"They will know that Anfield is a difficult place for them. I know they can say it is not a problem and they have experienced it before, but we know it will be a problem for them.
"Our supporters, they are the special ones, that is clear. Chelsea know why."
Two years ago, the Anfield hordes roared their team into the Istanbul final on a memorable night against Chelsea, and Benitez believes they can do it again, with the Merseysiders 1-0 down from the first-leg.
He said: "We can use the memories of two years ago to our advantage because we know what the players and fans can do working together.
"I remember before the game in 2005, the Chelsea players spoke a lot about being ready for the Anfield atmosphere, but when the game was played they could not handle it. It's very difficult for any opposing team to prepare to play against 12 men.
"Our fans cannot give red cards or award penalties, but they can score goals. I like this about our supporters because we know they will show they are in the best in the world again tomorrow night.
"The players can also use these positive memories. We will go into the game with a lot of confidence, but we know Chelsea are a very good team and we cannot afford to make mistakes.
"They are a team which has been built with a lot of money to win major trophies. They spent a lot of money on [Andriy] Shevchenko and [Michael] Ballack last year because their priority is the Champions League. Now they have more difficulties in the Premiership, it's clear if they're going to win a major trophy, this is the one they want to win."
And Benitez reveals he has spent time working on the mistakes made in the first leg last week at Stamford Bridge.
He said: "We are trying to learn from our mistakes in the first leg, they are very good, but I have confidence because playing with 12 men is a great advantage for us.
"It is no secret we will try to play with a high tempo from the beginning, something we didn't do in the first-leg. If we can keep a high tempo going for 90 minutes, that will be perfect.
"We did not play to our best level in the first leg, that is the key for me.
"If we play to our best, we will win."