Juventus frozen out in Poland
Juventus were held to a 1-1 draw by Polish champions Lech Poznan in Group A, their fifth in as many matches, in freezing weather which made a snow-covered pitch almost unplayable.
Second-placed Lech are three points ahead of Juventus and have a better head-to-head record on away goals after their 3-3 draw in the reverse fixture. Manchester City went top of the group and secured a berth in the last 32 with a 3-0 win over Salzburg.
Flamboyant Italian striker Mario Ballotelli scored twice for City at Eastlands and winger Adam Johnson added the third in the closing stages.
Zenit St. Petersburg made it five wins out of five in Group G with a 3-1 home success over Anderlecht and AEK Athens are in a good position to join them after beating Hajduk Split by the same score on a pitch resembling a quagmire.
Having scored a hat-trick in Lech's 3-3 draw with Juventus, Latvian striker Artjoms Rudnevs returned to torment the double European champions and triple UEFA Cup winners in front of a raucous home crowd braving the cold.
Rudnevs headed in a 12th-minute corner by Bosnia midfielder Semir Stilic and Lech keeper Krzystof produced a string of superb saves before Vicenzo Iaquinta, wearing a skiing cap like many of this team-mates, set up a dramatic finish.
Juventus, wearing white shirts, were almost as invisible as the ball on a snow-covered pitch in the first half and although they improved after the break, Lech held on in the closing stages to send their fans into raptures.
Atletico, beaten by Aris 1-0 in their first match, are level on points with the Greek side in Group B but behind on head-to-head, meaning that progress into the knockout stage is no longer in their own hands.
Atletico are now at the mercy of eliminated Norwegians Rosenborg, who must do them a favour away to Aris if the holders are to progress with a result against group winners Bayer Leverkusen. The 1988 UEFA Cup winners clinched the group with a 1-0 win at Rosenborg.
Sergio Koke fired Aris into a second-minute lead but Atletico looked set to seal a berth in the last 32 after Diego Forlan and Sergio Aguero struck shortly afterwards.
Koke drew level with a penalty soon after the break before Nikos Lazaridis silenced the Vicente Calderon faithful in the 81st minute.
Italy striker Giampaolo Pazini fired Sampdoria ahead against PSV Eindhoven on the stroke of half-time but the Dutch side stormed back thanks to a brace from Swede Ola Toivonen to stay top of Group I on 13 points.