Rooney and Giggs key in Mata's absence against Olympiacos

Wayne Rooney and Ryan Giggs can help make up for Juan Mata's absence when Manchester United take on Olympiacos in their Champions League.
 
United meet Olympiacos in Athens tomorrow night for their first-leg round of 16 tie.
 
And David Moyes's side will be without Mata in midfield - as he is ineligible having already played in the competition for Chelsea.
 
However, with Rooney dropping deep to pick up the ball and Giggs' experience in the middle of park United can cope without their £37million man.
 
Here, Express Sport looks at some of the likely key battles on the pitch.
 

AVRAAM PAPADOPOULOS v WAYNE ROONEY

Olympiacos captain Papadopoulos will be charged with the unenviable task of keeping Rooney in check at the Karaiskakis Stadium. The Greek international missed out on this season's group stage games through injury and will have to make sure Rooney's recent run of relatively poor goalscoring form continues.

ALEJANDRO DOMINGUEZ v RYAN GIGGS

Argentinian playmaker Dominiguez already has seven goals this season and Giggs will need to make sure he has minimal space to give support to Javier Saviola up front. United's midfield has faced criticism this year but generally performed well in Europe and Giggs will hope he can inspire a performance similar to their 5-0 win at Bayer Leverkusen.

JAVIER SAVIOLA v CHRIS SMALLING

Now 32, Saviola is a striker with a wealth of experience from spells at Barcelona and Real Madrid and with 40 caps for Argentina's national side. His two goals in the final group stage game against Anderlecht showed he can still be dangerous in Europe. Smalling is still a raw talent at United but will be keen to impress Moyes after a good performance in the goalless draw at Arsenal last week.