Here we consider where the game will be won and lost.

JOAO MOUTINHO v NANI Nani has made an exciting start to his United career and will be looking forward to returning to a stadium he left only a matter of months ago.

His form for Sporting was impressive enough to earn him a big-money move to Old Trafford but his former team-mates will be well prepared for his stockpile and tricks and flips.

Moutinho, Sporting's youthful captain, is a promising link-up man between midfield and attack and will be looking to exploit the space in front of the back four. With Owen Hargreaves ruled out due to a thigh strain, United are shorn of their defensive shield and more likely to play an attacking game suited to the rapid 20-year-old.

Whichever player can get on the ball most often could dictate the pace of the game could hold the key.

LIEDSON v RIO FERDINAND The Brazilian striker has yet to taste international football despite his publicly-stated willingness to switch his allegiance to Portugal, but he is nevertheless a handful in the box.

His scoring record is good for Sporting and he his speed and control have made him a favourite in Lisbon.

Ferdinand, though, will not be scared by his pace and has the physical attributes to shackle his opponent.

But he must not be sucked into joining the attack or he could be caught out.

ANDERSON POLGA v CARLOS TEVEZ As part of the 2002 World Cup-winning squad, Polga is used to the big occasion.

He is a strong but cultured centre-half and attracted plenty of interest from all across Europe before committing himself to Sporting.

Tevez has yet to reproduce the displays which inspired West Ham's unlikely survival last season but he has all the qualities to make him a genuine star.

He was a key part of Argentina'sCopa America side in the summer, perhaps a reason for his slow start this term, and if he can locate his best form he can spearhead United's efforts in the Champions League.