Benfica defender Luisao says they must target Wayne Rooney to stand a chance of beating Manchester United on Wednesday.
The Portuguese club host the Premier League champions as the UEFA Champions League group stages get underway.
Benfica were knocked out of the competition in the first round last season but have made a solid start to their new Primeira Liga campaign.
Manchester United, last year's finalists, have been unstoppable so far this season, with four wins out of four and Rooney has scored eight goals in those games.
Benfica represent the Red Devils' toughest challenge in the group stages, with FC Basel and Otelul Galati making up Group C.
Brazilian veteran Luisao told skysports.com: "The key to winning will be how we do defensively.
"We need to stop Wayne Rooney to win the game. He is a star worldwide but even players like him can have off-days.
"Rooney is not the only danger in the Manchester United side. All their players can create problems for us.
"We know that we have to be near-perfect to win the game and that is our challenge."
Sir Alex Ferguson is expected to name an experienced line-up, with Michael Owen and Ryan Giggs included in the squad.
Portuguese winger and former Sporting star Nani should also make an appearance, and Luisao is wary of the 24-year-old.
He said: "Nani is also an important player for them and playing in his own country may be an added incentive for him.
"The English can be the worst teams to play against but we do not fear them. Benfica is an historical club in Europe and our dream is to create more history.
"United have started the Premier League season in spectacular form but it is not easy to reach the same level each day.
"We are optimistic and I believe that United and Benfica will make it to the next round.
"Any footballer dreams of being involved in this type of match."