Sissoko has been told to rest and will be examined again next week, but in the meantime, Benitez is having to revise his team plans radically for the coming weeks.

And it could signal the premature end of Benitez’s decision to use skipper Steven Gerrard on the right of midfield, having failed to secure a right winger during the transfer window.

Starting with Sunday’s home Barclays Premiership game with Manchester City, Gerrard should find himself employed back in his best position in the centre of midfield.

Sissoko is currently in London under the care of “the best specialists in the country,” says chief executive Rick Parry, the Mali international having suffered severe damage to his right eye during Tuesday’s Champions League 1-0 defeat in Lisbon.

A new statement from a club spokesman this afternoon said: “We are glad to report there has been an improvement in Momo’s condition over the past 24 hours, with the progress described as ’encouraging’.

“The player was examined this morning by a leading eye specialist who remains optimistic, despite reports emanating from Lisbon.

“Momo has been instructed to rest completely and will be examined again by the specialist next week.”

Sissoko needed to stay on in a Portugal hospital for further checks overnight where reports suggested his sight could be “compromised”, before he was allowed to fly back to the UK with the club aware by then the midfielder they signed last July for £5.6m (€8.3m) from Valencia had badly damaged the retina in the eye.

His loss will be devastating to Liverpool’s plans. His value is underlined by a statistical assessment of Premiership midfielders earlier in the season that revealed the average work rate among them is around eight kilometres of running per game.

Those same figures showed Sissoko on average covers 12km a match.

Benitez will now have to shuffle his midfield pack and make sure he replaces the high energy work of Sissoko – a key figure in all his plans this term – with the one player the Spanish coach has on the staff who could do the job, and that means Gerrard.

German midfielder Dietmar Hamann, whose 22 appearance so far this season has triggered a new one-year contract in the summer, does not have the mobility these days to do Sissoko’s job while Xabi Alonso is required to produce the quality passing.

It also means Luis Garcia, who has been injured and spluttered in and out of the side of late, could get a more regular run on the right of midfield.

With Jamie Carragher suspended against City and Robbie Fowler not involved under the terms of his recent transfer back to Anfield from the Manchester club, the damaging loss of Sissoko is another problem Benitez does not need ith the FA Cup, Champions League and a Premiership top-four spot still the targets.

Parry tried to play down fears Sissoko’s sight is in danger in his right eye, but it is clear the club do expect this to be a serious injury that will take time to heal.

Parry said on Liverpoolfc.tv: “We don’t want to sound too pessimistic because it’s too early to tell.

"What Momo needs right now is our support and the best care he can get.

“His right eye is closed down and it’s been difficult to assess the damage because of the swelling and bleeding.

“However, it’s too early to jump to conclusions. Obviously this is a very traumatic time for Momo and the club is in constant contact with his family and representatives. It’s a very nasty injury.

“He’s now in London being treated by the best specialists in the country.”