Rafael Benitez has warned Liverpool fans that his side face an extremely tough task as they seek to overturn a 1-0 first leg deficit in their Europa League last-16 second leg tie at Anfield on Thursday. Morale has been boosted in the Liverpool camp by a 4-1 win over the Premier League's bottom side, Portsmouth, on Monday night. But Benitez cautioned that the European fixture is likely to be a more cagey affair. 'Everyone wants to see attacking football and we try to approach every game in the same way and sometimes you can but sometimes you cannot,' the Spaniard said. 'We knew we needed to push Portsmouth from the beginning because they are not having an easy time but that was a different game. 'Against Lille, we have to make sure we do the right things: score, keep a clean sheet and do good football things.' The Europa League represents Liverpool's last chance of silverware this season and Benitez expects his squad to rise to the occasion. 'The fans know this is the last opportunity to win a trophy so hopefully there will be a good atmosphere. And the players know it is the last opportunity to win silverware so everyone will try their best tomorrow.' Italian midfielder Alberto Aquilani, who was outstanding against Portsmouth, is doubtful for Thursday's match after going down with a bug. 