Jurgen Klopp says Liverpool will be ready to put up a fight when they take on Villarreal in the first leg of their Europa League semi-final tie at El Madrigal on Thursday.

The Premier League side are being plagued by injury problems and will be without a number of first-team regulars in Spain.

However, Klopp remains optimistic about his side's chances and does not think their busy schedule and injury concerns will be a major obstacle.

"Momentum is not about having the best squad ready to play. Momentum is to be ready to fight," Klopp told the Liverpool website.

"Villarreal also have had a lot of games. They play after our game against Real Sociedad and have a little fight for the Champions League.

"We need to be prepared. It isn't about always having the best players but being perfectly prepared for our next game. Then we can progress."

Klopp will be without Christian Benteke (knee), Emre Can (ankle), Joe Gomez (knee), Jordan Henderson (knee), Divock Origi (ankle) and Danny Ings (knee) on Thursday.

Villarreal, meanwhile, are desperate to make it to the final of a major European competition for the first time.

They stumbled at the penultimate hurdle against Valencia in the UEFA Cup in 2003-04 and versus Arsenal in the Champions League in 2005-06, while Porto proved to be too strong in the Europa League in 2010-11.

Attacking midfielder Denis Suarez won this competition with Sevilla last season and he is eagerly anticipating the clash with Liverpool.

"Villarreal have already been close a few times, but only just missed out, so we are all determined to make it to the final this time," Suarez told EFE.

"Liverpool are a team with a lot of history and that only further motivates us. It is never easy to play in a semi-final and it is great to be there again after last season with Sevilla.

"I expect it to be two very entertaining games. We are two teams that like to attack, so I think it will be an open tie. 

"Liverpool have perhaps not been great in the Premier League, but they are doing very well in Europe."

Villarreal will be without Leo Baptistao due to an unspecified injury, while Jaume Costa (thigh) and Mateo Musacchio (thigh) are both doubtful.

Key Opta facts:

- This will be the first meeting between Villarreal and Liverpool in Europe.
- Villarreal are winless in their last 10 games against English opposition.
- This will be Liverpool's fourth European semi-final against a Spanish side.
- Only Athletic Bilbao striker Aritz Aduriz (10) has scored more Europa League goals than Villarreal's Cedric Bakambu (nine) this term.
- Jurgen Klopp emerged victorious in his only previous semi-final in European competition as a coach, seeing off Real Madrid over two legs in the 2012-13 Champions League.