Last season's finalists AC Milan and Liverpool were stunned in their group games in the UEFA Champions League on Wednesday.

A last-minute goal from Scott McDonald gave Celtic a 2-1 victory over holders AC Milan in their Group D clash while Olympique Marseille stunned Liverpool with Mathieu Valbuena's classy goal earning a 1-0 win at Anfield in Group A.

Valbuena took a return pass from Bolo Zenden before curling in a 25-metre shot off the underside of the bar in the 76th minute after Momo Sissoko was tackled just outside his area.

But it was not a fluke victory for new coach Eric Gerets in his first game in charge of a Marseille side that has won just one of their nine domestic league games this season.

Liverpool did not really threaten until the final minutes when Fernando Torres hit the post with a close-range shot.

AC Milan match ended on a sour note as goalkeeper Dida was carried off on a stretcher after being struck in the face by a supporter who raced on to the pitch to celebrate.

Celtic went ahead after a dull, rain-lashed first half when captain Stephen McManus bundled in a close-range shot at the back post after Aiden McGeady's corner skidded across the face of goal in the 62nd minute. The ball took a last touch off Milan's Yoann Gourcuff.

The Italians levelled from a penalty six minutes later with Kaka [Images] sending Celtic keeper Artur Boruc the wrong way, before McDonald grabbed the late winner.