Liverpool FC boss Rafa Benitez stands firm on Robbie Keane decision

Benitez has previously clashed with Gillett and Hicks, who are believed to be struggling to refinance loans they used to purchase the club, over transfer budgets.

And the American pair are unlikely to be impressed that such a major transfer investment is being so scantly used. However, Benitez brushed aside any concerns and suggested he expects more £20m players to arrive next year.

"I don't think about this, only about the team," he said." "I think that next year they will be really worried about different players worth £20m on the bench every single week."

Benitez defended his tactics as Hull held Liverpool to a third consecutive Premier League home draw on Saturday.

With Liverpool chasing a first Anfield league victory since early November after Steven Gerrard's brace cancelled out Paul McShane's opener and Jamie Carragher own goal, Benitez threw on Ryan Babel, Nabil El Zhar and Lucas.

It was Benitez's final replacement, which confined Keane to the role of unused substitute, that was greeted with greatest dissatisfaction, with sections of the Anfield crowd booing the decision.

But the Anfield chief, who admitted his disappointed at the result, stood by his decision to call on Lucas instead of Keane.

He said: "We wanted to keep (Xabi) Alonso in the middle trying to control midfield, because Javier (Mascherano) was going too hard and Lucas is a player that can get into the box really well. He has the quality to deliver a final pass.

"I wanted more quality in the middle. Mascherano is a defensive midfielder, Lucas is more offensive. He can pass the ball and he is more precise.

"You have to think about winning," he added. "For me, the best thing was to use wingers and an offensive midfielder that can pass the ball better, because in the last minutes of the game you need someone calm who can pass the ball better. To put more people into the box and start playing long balls is not the solution."

Shrugging off concerns that Keane's confidence, which has already been tested by a difficult beginning to his Anfield career, would be affected Benitez said: "Everybody has to be disappointed today. We have drawn a game at home today that normally everybody would have expected to get three points.

"But the decisions were tactical. El Zhar did well, as did Babel. We needed an attacking midfielder because the other team was sat very deep."

The events will prompt further speculation about Keane's future, with the Irishman having been linked with a swift return to former club Tottenham Hotspurs in the January transfer window.

However, the striker, who played a full 90 minutes for only the fourth time this season against PSV on Wednesday, last week reiterated his desire to prove his worth to Liverpool and Benitez said: "It was positive (to hear Keane committing to Liverpool). In a club like this all the players know that they will have opportunities. He is training hard, but we need different solutions in different games.

"All the players want to play," he added. "He will be thinking the same as Ngog, another striker who played really well the other day. He scored a goal and will be thinking, 'why not me?.

"But this is normal. They have to understand that they need to work within the squad."

Anfield's American owners George Gillett and Tom Hicks are bound to question the wisdom of shelling out £20m on a striker who Benitez does not play.

The manager, however, insisted he was unconcerned and hinted that he expected his bosses to sanction further big-money spending next summer.

"I don't think about this, only about the team," he said.

"I think that next year they will be really worried about different players worth £20m players on the bench every single week."

Another of Benitez's summer signings also endured a trying afternoon, as Andrea Dossena's miserable form continued with the £7m defender badly exposed for both of Hull's goals.

But Benitez praised the Italian's attacking contribution, saying: "He was really good going forward. He delivered two or three very good crosses.

"He played well in his last game. He was much better. And today his attacking was really good.

"Defensively as a team we made mistakes, because (Jamie) Carragher (scored the own goal). We can talk about two or three players (who were at fault) for both goals."