PARIS (AFP) - After performances ranging from inconclusive to dismal in their opening games, Manchester United, Manchester City and Inter Milan must step up a gear in their second Champions League outings on Tuesday (today). Although the trio will be fully aware that no club has retained the trophy since the league format was introduced 20 seasons ago, most observers agree it will take a Herculean effort to wrest the cup from Barcelona. Dethroning the Catalan club will certainly demand an improvement on Uniteds opening draw at Benfica, Citys stalemate at home to Napoli on their Champions League debut and Inters shock home defeat by Turkeys Trabzonspor. City, joint-top of the Premier League with United, suffered from nerves in their opener against Napoli, who held them 1-1 at the Etihad Stadium to leave manager Roberto Mancini admitting his expensively assembled side had been nervous because it was the first game. But he predicts that the pressure has now subsided as City for whom Carlos Tevez could feature with weekend goal hero Mario Balotelli suspended head off to their first away encounter in Group A. The sides have never met before but Bayern have the edge in experience, even if City can boast four former winners in their squad in Tevez, Balotelli, Owen Hargreaves and Yaya Toure. Bayern have already laid down a marker by winning 2-0 away to Villarreal and a win on Tuesday (today) would almost give them a foot in the next stage. Bavarian confidence is sky-high after a weekend drubbing of Bayer Leverkusen moved them two points clear in the Bundesliga. Midfielder Bastian Schweinsteiger said the whole side was looking forward to the clash but warned this is probably our toughest match of the season so far, a real challenge. Napoli will bid to stay in the mix by inflicting more woe on Villarreal, who knocked the Italians out of last seasons Europa League. Manchester United, meanwhile, have to tackle Swiss side Basel without the services of hamstring victim Wayne Rooney. Manager Sir Alex Ferguson is pondering his most effective line-up in Rooneys absence, while awaiting news of the extent of the injury Javier Hernandez suffered in Saturdays 1-1 draw at Stoke, which ended Uniteds perfect start to the league season. Basels coach Thorsten Fink has a special reason to want to put one over United, as he was in the Bayern Munich side that lost the dramatic 1999 final to the Red Devils in Barcelona. Inter will hope their nightmare start to the campaign is over after sacking Gian Piero Gasperini and bringing in former Chelsea and Juventus boss Claudio Ranieri. Ranieri got off to a winning start with a 3-1 victory at Bologna on Saturday, but playmaker Wesley Sneijder, Brazil full-back Maicon and Serbian midfielder Dejan Stankovic will miss the Group B meeting with CSKA in Moscow. In the same group, French champions Lille visit Trabzonspor, having thrown away a 2-0 lead to draw 2-2 at home to CSKA in their first fixture. In Group D Lilles compatriots Lyon tackle Dinamo Zagreb, while Real Madrid host Ajax, who they helped eliminate at the same stage of last seasons competition. Real Madrid president Florentino Perez has once again spoken of his clubs obsession with winning a 10th Champions League title ahead of todays (Tuesday) clash against Dutch giants Ajax. Real know a victory will be enough to secure a stranglehold over a Group D which also includes Lyon of France and Croatias Dynamo Zagreb. After a first match day 1-0 victory at Dynamo, a perfect home record will almost guarantee the most successful club in the competitions history a passage into the knockout stages. The form book says that Real Madrid should prevail. When the two teams met in the same group stages of last seasons competition Madrid recorded a 2-0 victory in the Santiago Bernabeu before scoring four goals without reply in Amsterdam. However for a club without a Champions League title in the last 10 seasons Real Madrid cant afford to be complacent. And recent league results have raised doubts about the early season form of Jose Mourinhos team. Although a Cristiano Ronaldo hat-trick helped them to a 6-2 victory at home to Rayo Vallecano on Saturday, two disappointing away performances losing 1-0 to Levante and drawing 0-0 with Racing Santander in the past week had the alarm bells ringing. So much so that Perez also took advantage of Sundays meeting to send a message of support to Mourinho. Real will have to do without Brazilian full-back Marcelo Vieira, who was red-carded in Zagreb and is banned, as well as Pepe and Fabio Coentrao who picked up injuries in the last week and did not train on Sunday. Ajax could only draw 1-1 on Saturday at home to FC Twente. Their goal from in-form Serbian striker Miralem Sulejmani made it five in six league starts for him this season. Sulejmani had been sidelined with a hamstring injury picked up against Lyon so his return is a plus for the Dutch. He should be joined by Icelandic forward Kolbeinn Sigthorsson as Ajaxs main attacking threats. Ajax will however be without young Danish defender Nicolai Boilesen who limped out of the recent 2-2 draw with PSV Eindhoven and is set to be sidelined for six weeks.