Manchester United walk out at the site of their 2008 Champions League triumph today with manager Sir Alex Ferguson warning his side that the days when they could cruise to victory against the competition's lesser names, in particular from eastern Europe, are rapidly disappearing.

United face CSKA Moscow on the artificial surface of the Luzhniki Stadium, where they beat Chelsea on penalties in May 2008 to lift the trophy for the third time. Mindful that a third group stage win will virtually clinch his side's place in the knockout rounds, Ferguson said: "The Champions League for a few years now has had a tremendous amount of quality in it. I think the Russian teams in particular have improved a lot in the last few years thanks to big investment."

"There are a lot of Brazilian players in Russia now," he added. "So you can expect a difficult game there and it's a surface which we're not used to playing on."

A number of United players have not made the trip to Moscow, including Wayne Rooney, whose wife is about to give birth to their first child, but they will expect to avoid defeat in the tea-time kick-off against a club who recently brought in the former Tottenham manager Juande Ramos to take over from the Brazilian Zico.

In tonight's other game involving an English club, Chelsea know they have to tighten up defensively when they take on Atletico Madrid at Stamford Bridge. Two set-piece goals were their undoing against Aston Villa on Saturday and midfielder Michael Ballack has admitted the players are concerned.

"We have no problem criticising each other in the dressing room," Ballack said. "A good team with strong players has to do this. We've done that, then we shake hands and get back on to the training pitch and try to do better."

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