Watford's hopes of beating relegation have taken a blow with forward Gerard Deulofeu set to miss the rest of the season.
The Spaniard ruptured his anterior cruciate ligament and tore his meniscus during the 3-0 win over Liverpool on Saturday.
He will now undergo surgery and boss Nigel Pearson admitted the attacker will be a big miss for the Hornets, who moved out of the relegation zone on goal difference with the weekend victory over the Premier League leaders.
An official club statement read: "Deulofeu is set for surgery after scans confirmed a ruptured ACL and torn meniscus suffered during the first half of our win over Liverpool."
Head coach Pearson added: "Unfortunately for him and us, the scan results really show he is probably going to be out for the rest of the season.
"For sure Geri is going to be a miss for us; but equally it's important we look forward with a positive mentality. (Roberto) Maxi Pereyra went in for Geri and I thought he did very well when he went on.
"It almost goes without saying that we'll give Geri all the support he needs for a full recovery."
Deulofeu suffered the injury in the 32nd minute and left the pitch on a stretcher after a five-minute delay.
Captain Troy Deeney said: "It's going to be a real tough one and we wish him well. I said to him at half-time: 'We're going to win this for you', and thankfully we did."
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