Here we assess how the clubs match up.

EUROPEAN PEDIGREE

United are the reigning champions with Sir Alex Ferguson leading the team to their second Champions League title of his tenure. The penalty shoot-out victory over Chelsea in Moscow saw them lift the European crown nine years after they beat Bayern Munich in a last-gasp victory. It was their third victory overall after becoming Europe's top team in 1968. The 1991 Cup Winners' Cup, and European Super Cup of the same year, are United's other European trophies.

Celtic were the first British club to be crowned European champions when they beat Inter Milan in the final in 1967. The players became known as the Lisbon Lions and were all born within a 30-mile radius of Celtic Park. They again reached the final in 1970 before losing to Feyenoord. The Scottish champions have reached the last 16 for the last two seasons where they have been knocked out by AC Milan and, last year, by Barcelona. In 2003, the Scots were beaten in the UEFA Cup final by Jose Mourinho's Porto.

FORM

The Barclays Premier League champions are starting to tick after a stuttering start to the season and are benefiting from the fine form of Wayne Rooney who can be unstoppable. Although the Red Devils hit four against West Brom on Saturday, it was only the third time this season they had scored more than one goal in a league game. Dimitar Berbatov opened his league account as the team adapt to having even more attacking options. United are now fifth in the table with a game in hand and looking ominous.

Celtic are three points clear at the top of the SPL ahead of rivals Rangers, who have a game in hand, following the weekend win at Inverness. Celtic have lost only once at home all season - albeit to Rangers - and they have been relentless despite being depleted by injuries to key players. However, their away form in Europe is abysmal with just one point from 16 games.

PLAYERS

United have many household names in their squad while Celtic have few players who would be recognised south of the border. The Old Trafford outfit have an abundance of riches up front with Rooney one of the in-form players in the Premier League as well as Berbatov with the two still yet to fully fire. Ferguson can also call on Carlos Tevez and Ryan Giggs with Cristiano Ronaldo, Nani and Anderson all contributing in attack. Rio Ferdinand and Nemanja Vidic can be imperious at the back with Paul Scholes and Michael Carrick doing hard work - a lot of it unnoticed - in midfield.

Celtic are depleted by injuries with forwards Jan Vennegoor of Hesselink and Georgios Samaras - once of United's local rivals City - both ruled out. Scott McDonald is a pacy, nippy forward who can score key goals. Shaun Maloney joined from Aston Villa in the summer while many will remember Shunsuke Nakamura who scored with a superb free-kick in the teams' last meeting.