Manchester United manager Sir Alex Ferguson has warned his players to "respect" Benfica during Wednesday's meeting between the two sides.
Ferguson's side travel to Lisbon for their first match in this season's Champions League and the boss has revealed that he is wary of the threat posed by the Portuguese club.
As a result, the 69-year-old has claimed that he will call upon some of his more senior players for the fixture.
"My team in Lisbon might be different on an issue of experience," Ferguson told United's official website.
"We've also got Darren Fletcher back fit. He's looking good and did well with Scotland last week. I think we'll need to have more experience in the game.
"The important thing is to qualify. Benfica away from home is the kind of the game you have to respect."
United's other two group opponents are FC Basel of Switzerland and Romanian champions Otelul Galati.