This Tuesday, the eyes of the football world will once again be fixed firmly on the Camp Nou, as Barcelona and AC Milan, two of the most decorated sides in Europe, face off for a place in the UEFA Champions League semi-finals.Elsewhere, Bayern Munich, Chelsea and Real Madrid will all be hoping to avoid major upsets at home and progress to the last four on the back of respective first-leg victories over Marseille (2-0), Benfica (1-0) and APOEL Nicosia (3-0).Match of the day Barcelona-AC Milan, Camp Nou, Barcelona, 20:45 For the fourth time in this season’s Champions League, Barcelona and AC Milan are about to lock horns. In the group phase, Barça recorded a 2-2 draw at the Camp Nou before winning 3-2 at the Stadio Giuseppe Meazza. It was a different story in the pair’s most recent clash, however, as the Catalans could only manage a goalless draw in Milan, despite having 17 shots on target. This time around, a draw will not be enough for Pep Guardiola. “We needed a goal,” rued the Barcelona coach ahead of the return leg. Meanwhile, Zlatan Ibrahimovic, who had a quiet first leg, will no doubt be relishing his return to the ground of his former club, having found himself playing second fiddle to Lionel Messi for much of his spell.The two giants of European club football had contrasting warm-ups for Tuesday’s clash. Milan had to settle for a 1-1 league draw in Catania, while Barcelona came away with a 2-0 victory after a hard-fought encounter with Europa League revelations Athletic Bilbao. Success in the return leg would send the Catalans through to the semi-finals for the fifth season on the trot, and allow them to equal the longstanding record set by Real Madrid from 1956-60. Milan, meanwhile, will be looking to secure their first away victory in Europe this season.The other matches Bayern Munich-Marseille (first leg 2-0) Bayern broke the deadlock in the first leg at the Velodrome thanks to Mario Gomez’s eleventh goal in this year’s competition, and will probably feel that they have done enough to extinguish Marseille’s hopes of reaching the semis. With that goal, Gomez is now hot on the heels of Messi, who has 12, in the race to finish as this season’s top scorer in the competition. After a small dip in form, Bayern are now back in full flow both in Europe and the Bundesliga, where a recent 1-0 win at Nuremburg put them back to within touching distance of league leaders Borussia Dortmund. Marseille, for their part, are struggling in Ligue 1 and have it all to do if they are to secure European football next season. They will be without two key players for their trip to Bavaria, with Alou Diarra suspended and defensive rock Souleymane Diawara out injured.Chelsea-Benfica (1-0) Chelsea are unbeaten since their 3-1 first-leg defeat by Napoli in the last-16, and while under the stewardship of manager Roberto di Matteo. They have also tightened up defensively, which has helped to bring out the best in forward Didier Drogba. The Blues are the last English club in the competition, and they host Benfica on Wednesday knowing that they have never been knocked out of a European competition after winning a first leg away from home. The Londoners have also won all of their European home games this season, while Benfica have been inconsistent on their travels, with a record of one defeat, two wins and three draws. Chelsea are aiming for their sixth semi-final appearance in nine seasons, and they will no doubt be looking for every opportunity to punish their Portuguese opponents on the counter attack.Real Madrid-APOEL Nicosia (3-0) As the first Cypriot side ever to have reached the quarter-final stage, APOEL Nicosia will bow out of the tournament with their pride fully intact no matter what happens in Madrid. The Cypriots held firm until late in the first leg against a formidable Real frontline that has scored 140 goals in 46 competitive matches this season. There was certainly no shame in the 3-0 defeat, as that scoreline reflected Real’s average haul per game in this season’s Champions League, with 27 goals in 9 matches.Player to watch Luca Antonini, 29, is perhaps the least well-known player in the AC Milan side. The lively, athletic left-back played a vital role in the first leg against Barcelona, and did not put a foot wrong in marking Lionel Messi. The Milan native spent 11 years in the Rossoneri’s youth set-up, before playing for eight different clubs from 2001 and eventually returning to Lombardy in 2008. After facing stiff competition from Milan’s foreign stars for a place in the side, Antonini finally made his Champions League debut on 8 December 2009, but would not become a regular starter until the arrival of coach Massimiliano Allegri. The outcome of Tuesday’s quarter-final match is likely to depend, in no small part, on how well Antonini performs.The stat 74 – Of the 100 goals scored by Real Madrid in the Spanish top flight this season, 74 have come from the trio of Cristiano Ronaldo (37), Gonzalo Higuain (20) and Karim Benzema (17). French international Benzema leads the way in the Champions League, however, with seven strikes, ahead of Ronaldo on six and Higuain on three. The three forwards have scored a total of 99 goals in all competitions this season.What they said “We couldn’t have hoped for better in the first leg, as Benfica are very hard to beat at home. But we mustn’t get carried away. It’s not over yet,” Chelsea manager Roberto di Matteo.Have your say Can Marseille, Benfica and APOEL still turn things around after their first-leg defeats?FIFA.com looks forward to four games where, whatever the results, there is a pair of fascinating semi-finals in prospect, with the winners of Tuesday’s matches going head-to-head with Wednesday’s victors for a place in the final.