Liverpool boss Rafael Benitez is facing up to the worst injury crisis of his five years at the Reds' helm ahead of Sunday's visit of champions Manchester United.

Benitez will oversee a succession of scans and medical examinations on a host of his top stars following Tuesday night's 2-1 Champions League defeat at home to Lyon.

Liverpool have lost four successive matches for the first time since 1987, and are now in danger of dropping out of the title race and failing to advance from their Champions League group.

Benitez said: "We have just too many problems, I cannot remember an injury situation like this."

Fernando Torres and Glen Johnson both missed Tuesday night's game with groin injuries, while Steven Gerrard limped out of the match in the first half with a recurrence of the problem he picked up while playing for England last week.

Winger Albert Riera is also in need of a scan on his hamstring while teenager Martin Kelly's impressive full debut was ruined by an ankle injury.

And Benitez claimed his troubles do not end there.

He said: "There are other players with other problems, I have no idea what team I can put out against Manchester United until we have had the players tested and seen by the medical team."

Benitez, however, refuted suggestions that playing Gerrard was too much of a gamble and insisted his team can still qualify from Group E and reach the last 16.

Lyon maintained their 100 per cent

record at the top of the pool with Tuesday night's win, while Fiorentina's 4-3 victory in Hungary against Debrecen puts them in pole position to grab the second qualification spot.

Liverpool now must raise their game in their final three matches in order to progress further. They are away to Lyon in a fortnight, then travel to Budapest on November 24 before their final home game against Fiorentina on December 9.

The hosts led at half-time on Tuesday night through Yossi Benayoun, before crumbling under pressure to concede goals to substitutes Maxime Gonalons and Cesar Delgado - the latter in stoppage time.

Benitez said: "It was not a gamble to play Gerrard. He wanted to play and had trained normally for two days.

"He was given the all-clear by the doctor and it was just bad luck what happened. He felt something wrong in his groin, and it was wise to come off."

Liverpool have launched amazing recoveries in group stages in previous seasons to advance in Europe's premier club competition, and will need another one now.

Benitez said: "We have come back before, and we can do it again. We now must be ready for the next match. I have confidence that we have the quality to overcome these problems.

"We have to push players now, to keep working and to maintain our confidence."

The Spaniard also explained the decision to take off Benayoun and send on Andriy Voronin in the closing stages - a choice that was booed by the Kop.

Benitez said: "The fans know Yossi is a good player, but I felt he was getting a little tired and I wanted to use some fresh legs. We needed to change something, to put a fresher man on, and it was a chance worth taking."