Lucas looking forward to Zenit following Liverpool's thrashing of Swansea

Lucas believes Liverpool can still overturn a two-goal deficit against Zenit at Anfield. Photo: PA

Liverpool midfielder Lucas Leiva believes the morale-boosting demolition of Swansea was the ideal preparation for their Europa League tie later this week.

Reds boss Brendan Rodgers' former side were a shadow of themselves - distracted by Sunday's Capital One Cup final at Wembley - as they were dispatched 5-0 at Anfield.

The home side need goals on Thursday to overturn a 2-0 deficit against Zenit St Petersburg in order to reach the last 16 in Europe.

And having suffered back-to-back defeats, including a home loss to West Brom last Monday, Lucas thinks the goal rush provided the perfect antidote to a disappointing few days.

"We started the week thinking it could be a really good week for us," said the Brazil midfielder.

"But we had the defeat to West Brom and then the Europa League loss but we have finished the week off in a positive way by scoring five goals and keeping a clean sheet.

"We know we still have to improve a lot but this victory will give us confidence going into Thursday to try to get through against Zenit.

"With the way we played over there, we created a lot of chances, if we do that again and take them then we'll have a great chance of getting through to the next stage.

"But we also have to defend well on Thursday because if we concede an away goal it will be very difficult for us.

"We have to make sure we go with a positive and offensive mentality but knowing that if we concede it's going to be very hard."

Captain Steven Gerrard's 34th-minute penalty provided the crucial breakthrough, succeeding from the same spot from which he had failed against West Brom.

Lucas felt they had learned from the chastening Baggies experience, when they dominated but conceded twice in the last nine minutes.

"Unfortunately we couldn't score early but we kept going then towards the end of the first half we got the penalty.

"The second half we started really brightly and getting the second goal so quickly (after just 16 seconds) was very important and after that we just needed to make sure we controlled the game.

"We created a lot of chances and scored three more goals."

Inconsistency has dogged Liverpool for well over a year, preceding the reign of Rodgers who left Swansea to take over from Kenny Dalglish in the summer.

"It's difficult to explain. As players you get frustrated a lot of times as well," added Lucas.

"When you think we are starting to get some good momentum we have a defeat and a setback.

"But there is still time to get that consistency. Our league position is not great (seventh, nine points off the top four having played one match more) but we must keep fighting and see what happens.

"If we can get that consistency then we can finish this season on a high."

Swansea boss Michael Laudrup was hugely disappointed with the performance, which came after he rested seven players ahead of Sunday's Capital One Cup final as the club seek to win their first major trophy against League Two Bradford.

"Always when you lose you have to accept the criticism and I do that," he said.

"We paid the ultimate price because 5-0 is a big result. I hope this is a one-off.

"I hope it has happened because of what is going to happen at the weekend but it is no excuse.

"What happens next Sunday is more important than what happened yesterday.

"That was one of only 38 games. Sunday is maybe one of the most important games in the history of the club."