Manchester United: 6 Players to Watch as United Take on Benfica

There's something about Benfica versus Manchester United that simply oozes football romance.

Both clubs have fantastic individual pedigrees in the European Cup—Benfica are twice winners, United three-times—but they also have a distinguished shared history when dining at Europe's top table, dating all the way back to a certain match in 1968.

Back then it was George Best, Denis Law and Bobby Charlton who set United fans' pulses racing (although unfortunately Law was lying in a hospital bed on the night of his team's famous victory in the final at Wembley) while the incomparable Eusebio was the man who captured the hearts and imaginations of the Lisbon club's supporters.

These days it is the likes of Ryan Giggs, Wayne Rooney and Javier Hernandez who are worshipped as heroes in Manchester but with a huge Premier League clash against Chelsea on the horizon at the weekend, Alex Ferguson may be tempted to spring a few surprises in his line-up at the Estadio da Luz.

So who is likely to step up to the plate as a key protagonist in United's first match of this season's campaign?

What about Benfica? A strong start to the Portuguese Superliga season suggests they will be no pushovers, but who are the players most likely to cause problems for Sir Alex Ferguson and his team in Lisbon?

Sir Alex Ferguson has already identified the Argentine playmaker, Pablo Aimar as the main threat to any success his side might enjoy in Lisbon.

The 31-year-old midfielder arrived at Benfica from Real Zaragoza in 2008, but is probably best known for his time at Valencia, with whom he made his Champions League debut—against United—back in the 2000-2001 season.

That season he took the Spanish side all the way to the final, and his experience of Europe's top competition will be crucial to Benfica's chances against United.

Having suffered a below-par 2010-11 campaign, Aimar has shown signs he is back at his best this season. Forging a successful partnership with new signing Alex Witsel and Javi Garcia in the middle of the park.

Capable of unlocking any defence in the world when on song, Aimar will be charged with finding a way through United's back line—not an easy task, but one which he is capable of.

The 22-year-old former Standard Liege midfielder Axel Witsel, somewhat unfortunately, rose to wider prominence thanks to a horrific, leg-breaking challenge on Anderlecht's Marcin Wasilewski in 2008 and the subsequent replaying of his crime on Internet video sites.

But that moment of madness should not detract from the fact that Witsel is an excellent player and, fortunately this time, his career has not suffered.

With the eight-match ban meted out for his tackle served and memories of his indiscretion fading, he won a move to Benfica in the summer and has started his new career in Lisbon in blistering fashion.

He scored twice against FC Twente in qualifying for the group stage of the Champions League and it is that goal threat from midfielder that United will have to be wary of in Lisbon.

Another player who Ferguson greatly admires, Luisao has formed a solid central defensive partnership with Argentine Ezequiel Garay, both of whom will be charged with looking after Wayne Rooney on Wednesday night.

Luisao is one of those rare breeds of defender: imposing physically (he stands at 6'4"), yet equally as comfortable on the ball as biting into tackles.

The Brazilian is one of Benfica's longest serving players, having been at the club since 2003, but his latest partnership at the back may yet prove to be the best of the many he has enjoyed over the years.

Garay may only have arrived from Real Madrid over the summer, but early indications are that they are made to play with each other. For sure, they will have to be on top form if they are to keep the rampant Rooney quiet in their next outing.

Chris Smalling's rise to prominence has been nothing short of meteoric. To think that two years ago, he was playing occasionally for Fulham and could only dream of appearing in the Champions League.

Injuries to Nemanja Vidic and Rio Ferdinand - and some sterling stand-in performances at both centre-half and right-back—have given the 21-year-old his chance to feature in Lisbon, when he could be given the nod to start.

If he does, the cauldron that is the Estadio da Luz will offer him the latest test of his fledgling career, yet it is one which the Londoner is more than capable of passing.

Confident, physical and good with the ball at his feet, Smalling has already repaid the faith shown in him by Ferguson, who will have no compunction in pitting him against some of Europe's finest this season.

An early contender for signing of the summer, Ashley Young has been brilliant since making his move from Aston Villa.

He may be an England international, but Young's experience of Champions League football to date is non-existent.

What he does have experience of, though, is tormenting opposition full-backs and if he can keep up his blistering early season domestic form, he is sure give Benfica's back line plenty of headaches.

Indeed, Benfica fans will be hoping their team has done their homework on Young properly, considering how dangerous he can be when both providing and scoring goals.

Negate his influence on the game, and one of United's main arteries will be severed. Then, there's just the others to worry about, but targeting Young would be a good start for any club.

He announced his return from injury with a brace in his first start for United this season and watching the little Mexican on the pitch against Bolton at the weekend, it was like he had never been away.

The revelation of last season, Chicarito is a goal poacher extraordinaire. It doesn't matter if he's quiet for the majority of the 90 minutes, he has a true striker's knack of popping up when his team needs him most and finding the back of the net.

In his absence, United have fared pretty well, but with him back in the line-up, they look even stronger.

Benfica will be well aware of the threat he poses, and Luisao and Garay will have to be at the top of their game if they are to keep him quiet.