United's Wayne Rooney is in the form of his life with 32 goals for the club this season, while Liverpool's Fernando Torres has hit four in his last two games to take his tally to 17 in 27 appearances.

Torres has a better recent record against United than vice-versa, having been on target in his last two matches against the Red Devils.

Former Evertonian Rooney has not scored in 10 matches against Liverpool, his last goal coming in January 2005.

Liverpool head into the match on the back of two victories - over Portsmouth and Lille in the Europa League - in which Torres has scored twice in each.

Lucas believes that shows the Spaniard is almost back to his lethal best.

"The United match will be more difficult than the first two games this week because they are fighting for the title," said the Brazil midfielder, who is expected to keep his place in the side having been dropped for man of the match Alberto Aquilani against Pompey.

"They have a really good striker in Rooney who is scoring a lot of goals.

"Unfortunately Fernando has had too many injuries but he is back and has scored four goals in the last two matches to give us confidence.

"Of course it is not going to be easy but we have to believe we can win; the last two performances have been good and it gives us confidence.

"We can't go there looking to draw, we have to go there and try to get three points because it will be vital."

Defender Daniel Agger believes the threat posed by Torres is as great as that offered by United's front man.

"You have to recognise that he (Rooney) has scored some goals now and is a good player but we have a guy that scores some goals as well," said the Denmark centre-back.

"The game against Lille speaks for itself; he was fantastic and that is just what you need."

Forward Dirk Kuyt shouldered the goalscoring burden while Torres was sidelined for five weeks after an ankle operation in January but is delighted to see an impressive return for the striker, who celebrates his 26th birthday today.

"The form Fernando is in now is great for the team and hopefully he can do the same again on Sunday," said Kuyt.

"The reaction of the team has been good this week and we'll try to win every game between now and the end of the season."