PARIS (AFP) - Former European champions AC Milan and Aston Villa tumbled out of the UEFA Cup on Thursday as the lure of next season's mind-boggling Champions League riches proved a fatal distraction. Villa suffered a heavy price for downgrading Europe's second-tier competition when their second-string team slumped to a last 32 exit in freezing Moscow against CSKA. Milan, watched by less than 24,000 people at their San Siro home, also went out at the hands of Werder Bremen. They were joined on the UEFA Cup casualty list by Fiorentina, Tottenham and Valencia, but Manchester City and holders Zenit St Petersburg both secured places in the next round. Villa boss Martin O'Neill left the likes of Gareth Barry, Brad Friedel, Emile Heskey, James Milner, Gabriel Agbonlahor and Ashley Young back in England for the second leg tie against CSKA. The Russians took full advantage to carve out a 2-0 win on the night and a 3-1 aggregate victory to reach the last 16 with Yury Zhirkov and Vagner Love on target. "It's not a decision that was taken lightly," said O'Neill of his team selection which also included teenage debutants Barry Bannan and Marc Albrighton. "Circumstances forced me into making my decision." Peru striker Claudio Pizarro, on loan from Chelsea, scored both goals as Werder Bremen stunned Milan by coming back from a two-goal deficit to draw 2-2 and go through on away goals after the first leg had finished 1-1. Milan were cruising at half-time through goals from Andrea Pirlo and Pato but Pizarro's brace added to the misery for a Milan side who trail city rivals Inter Milan by a massive 11 points in the league. A Craig Bellamy double in the space of seven second half minutes ensured Manchester City a 2-1 win over FC Copenhagen for a 4-3 on aggregate. City are the only British side left in the tournament after a second-string Tottenham crashed out following a 1-1 draw at home to Ukrainian outfit Shakhtar Donetsk. Leading 2-0 from the first leg, Shakhtar only briefly looked in danger of relinquishing control of the tie after Mexican midfielder Giovani dos Santos opened the scoring with a stunning strike, ten minutes into the second half. But Fernandinho grabbed a late goal sealed Shakhtar's place in the last 16. With Sunday's League Cup final meeting with Manchester United looming, Spurs manager Harry Redknapp had made his priorities crystal clear by naming only one member of the side that defeated Hull on Monday in his starting XI. "Who am I supposed to play?," asked Redknapp who gave a debut to 18-year-old Jonathan Obika. "I must be in the wrong game if I'm meant to play a first team three days before the cup final." Fiorentina, fourth in Serie A, drew 1-1 at Ajax to exit 2-1 on aggregate with substitute Leonardo scoring an 88th-minute equaliser after Alberto Gilardino had put the Italians ahead. Valencia, also hopeful of a Champions League spot next season, were held to a 2-2 draw at home by Dynamo Kiev and went out on away goals. Sampdoria, struggling to avoid relegation from Serie A, were also big-name casualties when they lost 2-0 to Metalist Kharkiv in Ukraine having also lost the first leg 1-0. Defending champions Zenit St Petersburg enjoyed a 2-1 win at VfB Stuttgart to seal a 5-2 win on aggregate. The Russians struck just before half-time when Igor Semshov rifled his shot past diving Stuttgart goalkeeper Jens Lehmann from close range. Stuttgart hit back when 19-year-old Timo Gebhart beat three defenders and rifled his shot home on 80 minutes. But with a 3-1 deficit to overcome from the first leg, Stuttgart were always struggling to have a realistic chance of making the next round. Zenit made it 2-1 on the night on 85 minutes when Viktor Fayzulin smashed into the empty net. Martin Jol's Hamburg are also through after Croatia striker Ivica Olic struck as early as the ninth minute, his goal enough to seal a 1-0 win over NEC Nijmegen and a 4-0 aggregate success.