MILAN, Sept 18 (Reuters) - Holders AC Milan will face Benfica and former midfielder Rui Costa on Tuesday when this season's Champions League group stages get underway.
The seven-times winners are without the injured Ronaldo and 39-year-old Paolo Maldini while Filippo Inzaghi, who scored both goals in the 2-1 victory over Liverpool in last season's final, is not assured of a start in the Group D clash at San Siro.
Liverpool, the 2005 champions, also face Portuguese opposition with a tricky trip to 2004 winners Porto. Also in Group A, Olympique Marseille return to the competition for the first time since 2003 when they host Besiktas.
Netherlands winger Arjen Robben could make his debut for Spanish champions Real Madrid at home to Werder Bremen with Lazio travelling to Olympiakos in the other Group C match.
Chelsea, semi-finalists last term, will be without striker Didier Drogba and midfielder Frank Lampard at home to Rosenborg Trondheim while Schalke 04 welcome Valencia in Group B.
Scottish champions Celtic visit cash-rich Ukrainians Shakhtar Donetsk in the other Group D match with the fixtures in Groups E-H taking place on Wednesday.