The 18-year-old will be on the bench for the Portuguese outfit after being named in a 19-man squad for the first-leg tie following his $1.8million move from Real Salt Lake in July.

Adu has long been hailed as a prodigy in the States, and despite his tender years Benfica coach Fernando Santos believes he has all the attributes to succeed in Europe.

"If the player has been named, it's because he's got the quality to be in the squad," Santos said.

"He's a player who has great potential with a brilliant future. But he's been training with us only a few days, so naturally there will be an integration process."

Strikers Oscar Cardozo and Nuno Gomes have also been declared fit and should play for the Lisbon-based side.

Elsewhere, a host of big names face potential banana skins in this week's first-leg outings as they attempt to qualify to the Champions league proper.

Last year's beaten finalists Liverpool face a trip to French side Toulouse while reigning two-time UEFA Cup champions Sevilla host Greek outfit AEK Athens on Wednesday.

Lazio host Dynamo Bucharest on Tuesday, the same night that Valencia come up against Swedish team Elfsborg.

The Spaniards will be the favourites to progress to the next round but striker David Villa is refusing to take anything for granted with the Swedish Allsvenskan already under way and the Primera Liga campaign yet to begin.

"We only think about playing in the next round of the Champions League," he told club website www.valenciacf.es.

"But we have to demonstrate on the pitch that we are a better team and that we really want to qualify.

"Our opponent has a better physical condition but we will try to counteract this with other things. Valencia has to defeat the Swedish team."