Benitez has named the Spain midfielder alongside the likes of Steven Gerrard, Jose Reina and Fernando Torres as one of the key components of his future plans.
Benitez's side last season came up just short in their pursuit of a first top-flight title since 1990, although a points tally of 86 marked their best effort of the Premier League era.
However, Benitez believes that with the addition of some fresh talent, they can overhaul bitter rivals Manchester United at the top.
And despite repeated speculation linking Alonso with big spenders Real Madrid, Benitez insists his compatriot will not be allowed to leave Anfield.
"We are working very hard to keep the spine of the team - that was always the idea," Benitez said.
"We have Pepe Reina as the No1 goalkeeper with Diego Cavalieri behind him, another good goalkeeper. Then we have (Martin) Skrtel, (Jamie) Carragher and (Daniel) Agger - three good centre-backs.
"Then you go to the midfield with Alonso, (Javier) Mascherano, Lucas and Gerrard, with Torres up front and (David) Ngog, who is a very good prospect. We have a good squad that is still young, so hopefully we can improve further.
"We know we still need to improve in some specific areas. We will be working very hard to do that over the summer."
Liverpool's long-term planning has been hampered by question marks over the financial constraints of owners Tom Hicks and George Gillett.
With the American duo and, therefore, the club struggling to cope with crippling interest payments on their massive debt, it has been suggested that any lofty ambitions might have to be shelved.
Striker Torres is, however, having none of it and has backed his team-mates to overtake Barcelona as Europe's top side.
"Our aim has to be the best. If we have no desire to be the best in England and in Europe then there is no point even turning up for work," the Spaniard said.
"I don't say it lightly, but we must think we can be as good or even better than (Champions League winners) Barcelona.
"It's the belief of everybody at this club that we can become the best and I think we have really moved forward in the last two seasons.
"Liverpool are just as famous as Barcelona as a football club and even more famous trophy-wise. But we want to make Liverpool as successful in this era as they were in the '70s and '80s."
Torres signed a contract extension to 2014 last month and he insists that, despite worries over the club's future, he has no desire to go elsewhere.
"There is nowhere else in Europe I want to be," he said.
"I believe we are on the verge of something special here and I am delighted to commit my future to this club.
"You would not get top players signing new contracts if they did not think there were good times ahead. I expect many trophies for Liverpool in the years to come."