PREVIEW:How this week's protagonists match up
Tuesday
AC Milan v Manchester United
Venue: San Siro
Kick-off: 7.45pm
On TV: TV3, Sky Sports 2.
Managers: Leonardo (40, Brazilian) v Alex Ferguson (68, Scottish).
Group stage: Milan finished second in their group, four points behind Real Madrid, winning just two of their six games. They only lost once, though, at home to bottom club FC Zurich, and managed to beat Madrid at the Bernabeu. United topped their group, their only slip-up a home defeat to Besiktas.
Ever-presents(in group stage): Alessandro Nesta, Clarence Seedorf, Andrea Pirlo, Massimo Ambrosini, Pato (Milan); Michael Owen (United).
Top scorer(in group stage): Pato, Filippo Inzaghi, Ronaldinho (2); Michael Owen (4).
Position in their domestic league: Milan 3rd (10 points behind Inter); United 2nd (two points behind Chelsea).
Odds to go through: United 8-15, Milan 11-8
Odds to win CL: United 15-2, Milan 20-1
When last they met: Milan knocked United out of the competition last time they met, winning 5-3 on aggregate at the semi-final stage in 2006-07.
Olympique Lyon v Real Madrid
Venue: Stade Gerland
Kick-off: 7.45pm
On TV: Setanta Ireland, Sky Sports 3
Managers: Claude Puel (48, French) v Manuel Pellegrini (56, Chilean).
Group stage: Lyon took the runners-up spot behind Fiorentina in Group E, their 2-1 win at Anfield all but ending Liverpool's hopes of progressing. They lost just once, away to the Italians. En route to winning their group, ahead of Milan, Madrid scored more goals (15) than any other team in the competition, Cristiano Ronaldo getting six of them.
Ever-presents(in group stage): Cris, Aly Cissokho, Kim Kallstrom, Miralem Pjanic, (Lyon); Iker Casillas, Pepe, Raul Albiol, Xabi Alonso, Raul (Madrid).
Top scorer(in group stage): Miralem Pjanic (3); Cristiano Ronaldo (6).
Position in their domestic league: Lyon 4th (eight points behind Bordeaux); Madrid 2nd (five points behind Barcelona)
Odds to go through: Lyon 11-5, Madrid 3-10
Odds to win CL: Lyon 50-1, Madrid 9-2
When last they met: Lyon had the upper hand when they played Madrid in the Champions League in the 2005-6 and 2006-07 seasons, winning both home games and drawing twice in the Bernabeu.
Bayern Munich v Fiorentina
Venue: The Allianz Arena.
Kick-off: 7.45pm
On TV: Setanta Ireland, Sky Sports 2.
Managers: Louis van Gaal (58, Dutch) v Cesare Prandelli (52, Italian).
Group stage: Having lost home and away to group winners Bordeaux, Bayern needed to beat Juventus in Turin in their final game to go through – they did so, comprehensively, 4-1. Fiorentina had a less stressful passage, winning all five of their games (including Liverpool home and away) after losing their first to Lyon. Only Bordeaux won more points in the group stage.
Ever-presents(in group stage): Hans-Jorg Butt, Philipp Lahm, Bastian Schweinsteiger, Mario Gomez (Bayern); Gianluca Comotto, Marco Donadel, Juan Vargas, (Fiorentina).
Top scorer(in group stage): Ivica Olic and Thomas Muller (2); Adrian Mutu and Alberto Gilardino (3).
Position in their domestic league: Bayern 2nd (level on points with Bayer Leverkusen); Fiorentina 11th (21 points behind Inter).
Odds to go through: Bayern 1-2, Fiorentina 6-4
Odds to win CL: Bayern 14-1, Fiorentina 50-1
When last they met: The teams were drawn in the same group in last season's competition, Bayern winning 3-0 at home before drawing 1-1 in Italy.
FC Porto v Arsenal
Venue: Estádio do Dragão
Kick-off: 7.45pm
On TV: RTE 2, UTV
Managers: Jesualdo Ferreira (63, Portuguese) v Arsene Wenger (60, French).
Group stage: With Atletico Madrid and APOEL of Cyprus failing to mount any kind of challenge in Group D Porto cruised to a second-place finish behind Chelsea, who beat them home and away. Arsenal had no problems either, their only defeat coming in their final game when the group was already won – a weakened side lost 1-0 away to Olympiacos.
Ever-presents(in group stage): Bruno Alves, Hulk (Porto); Alex Song (Arsenal).
Top scorer(in group stage): Falcao and Hulk (3); Cesc Fabregas (3).
Position in their domestic league: Porto 3rd (seven points behind Benfica); Arsenal 3rd (nine points behind Chelsea).
Odds to go through: Porto 7-4, Arsenal 2-5
Odds to win CL: Porto 50-1, Arsenal 9-1
When last they met: Having already secured qualification for the knock-out phase last season Arsene Wenger sent a second-string team to Portugal - and they lost 2-0. By then, though, Arsenal had beaten Porto 4-0 at home.
Wednesday
